Allegations of Phoenix detective’s misconduct come to light in drive-by homicide case
The prosecution of a fatal drive-by shooting in 2020 has been complicated by multiple allegations of misconduct against the Phoenix homicide detective who investigated it.
The detective's disciplinary record raises doubt about the validity of 36 other criminal cases she was involved in investigating. It also brings questions about how the Phoenix Police Department addresses and reports officer misconduct, the scope of the problem, and how diligently the Maricopa County Attorney's Office tracks it.
Jennifer DiPonzio, then the lead detective in the case, quietly went on medical leave at the end of July 2021, after 20 years on the force. Defense lawyers for Eddie Vaughn, who had been arrested and charged with the shooting, were notified of the detective’s leave only after repeated unsuccessful attempts to interview her.
In November 2022, well over a year after Vaughn was indicted, the Maricopa County Attorney’s Office notified defense lawyers that they had recently discovered an open Professional Standards Bureau investigation into DiPonzio’s actions. The PSB is the internal affairs department of the Phoenix police, which investigates misconduct.
Prosecutors say they did not have prior knowledge of this investigation nor any of the numerous other inquiries the PSB conducted into DiPonzio. Her internal affairs file runs 14,000 pages and dates to as early as 2013, according to court records filed in the Vaughn case. It details more than a dozen allegations ― some minor, but others involving mishandling evidence and failing to interview key witnesses.
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Despite this, DiPonzio sought and got a lateral transfer to another squad within the homicide unit, seven years after the first known instance PSB looked at her work. Her husband, Nicholas DiPonzio, is an assistant chief at the Phoenix Police Department.
A lawyer representing Jennifer DiPonzio did not respond to a request for comment for this article.
And despite the multiple internal misconduct probes, her name does not appear on the county attorney’s “Brady List,” a database that prosecutors maintain of police officers with integrity concerns. The list is intended to ensure that both prosecuting and defense attorneys are aware of officers whose conduct may call into question their reliability as witnesses.
The list is named for the 1963 Supreme Court case Brady v. Maryland, which established that prosecutors must turn over evidence that is "favorable to the accused."
Former Maricopa County Attorney Rick Romley said that the office's Brady List began during his tenure. Romley said that an officer's presence on the Brady List is a "factor that goes into how a case is handled," from deciding whether to charge a case or whether to call that officer to testify. Maintaining the Brady List, Romley said, is the "mandate" of prosecutors.
Maricopa County Attorney's Office spokesperson Jennifer Liewer said, "Every witness, regardless of profession, is evaluated on a case-by-case basis and all issues are litigated appropriately."
Vaughn’s lawyer, David Le Lievre, claimed that it is “nearly impossible” that prosecutors only learned about DiPonzio’s misconduct in November 2022.
The scrutiny of DiPonzio comes two years into the Department of Justice's civil rights investigation of the Phoenix Police Department.
37 cases under review
In March, the County Attorney’s Office convened an umbrella hearing for 37 cases that DiPonzio played a role in investigating. DiPonzio had a varying level of involvement in each.
Of those 37 cases, 30 had murder or manslaughter charges. Ten have resulted in convictions. Six are ongoing cases where prosecutors have indicated that they are seeking the death penalty.
Two defendants were recently sentenced ― Kevontay Myers received 20 years and Benny Brooks III received two life sentences.
At the March 24 hearing, prosecutors asked Judge Jennifer Green to approve redactions made to a 24-page document. According to Le Lievre, prosecutors claimed that the document “represented the entirety” of the PSB investigation into DiPonzio. The document described multiple allegations of DiPonzio’s misconduct, including failure to impound audio recorded evidence and to follow up with investigations.
Deputy County Attorney Kirsten Valenzuela said the redactions were minimal and pertained only to ongoing homicide investigations.
A history of misconduct probes
It was at the March hearing that the scope of DiPonzio's activity exploded into view.
After that hearing, the Maricopa County Attorney’s Office facilitated Le Lievre’s June interview with Sgt. Jerry Barker, who was DiPonzio’s direct supervisor when she went on leave. Then DiPonzio's extensive disciplinary history came to light.
During the June interview, entered into court records, Barker told Le Lievre that DiPonzio did not complete her assigned tasks and would lie to him about doing so. He described becoming “more suspicious” of her over time.
After DiPonzio went on medical leave in July 2021, Barker discovered that she had failed to upload more than 50 audio interviews relating to various homicide investigations, according to court documents. Barker said he sent documentation of the recordings to his supervisors and was told PSB would take over the investigation.
Barker told defense lawyers that, in July 2022, he went to DiPonzio’s desk and found that it was “full of evidence and investigative notes.”
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When questioned, Barker said that he had wanted to examine DiPonzio’s desk earlier, but he had been given a direct command not to.
Though Barker updated his report to the Professional Standards Bureau, he revealed that he had never been contacted regarding it.
In a statement to The Arizona Republic, Phoenix police spokesperson Donna Rossi said, "The Phoenix Police Department takes the integrity of our investigations seriously. When the detective became unavailable, the Department transferred her cases to other detectives, as is the standard practice."
But Le Lievre claimed that there was never a formal PSB investigation into DiPonzio. In a court filing, Le Lievre wrote that the 24-page disclosure made by prosecutors consisted of, “by and large, Barker’s own work.”
During the June interview, Le Lievre also asked Barker if there had been previous allegations of DiPonzio’s misconduct. Barker said that there had been a prior PSB investigation.
The County Attorney’s Office said that its prosecutors had no knowledge of any history of DiPonzio's misconduct. According to court documents, it was only as a result of the Barker interview that they made a request for DiPonzio’s entire PSB file.
They said that those materials were received on June 12 and disclosed on June 23. They encompassed 14,000 pages and comprised 17 or 18 allegations of misconduct, stretching back to as early as 2013.
Court records show that DiPonzio removed a fingerprint card from evidence and did not return it for eight days. When DiPonzio and two other homicide detectives were interviewed, PSB found that “it is a customary practice in the Homicide Unit for detectives to leave evidence unattended and unsecured in drawers, under desks, and on top of desks.”
Another detective said that between October and December 2019, she saw three or four paper bags of evidence at DiPonzio’s desk. PSB found that DiPonzio had checked out 51 pieces of evidence during this period. PSB asked the Property Management Bureau to check the chain of custody for these pieces of evidence, but they said it was “logistically impractical.”
PSB could not determine whether DiPonzio had mishandled any of those 51 pieces of evidence, but the allegation of misconduct regarding the 2020 fingerprint evidence was substantiated.
Documents provided to ABC15 News showed that in August 2018, DiPonzio was named the Violent Crimes Bureau “Employee of the Month.” DiPonzio’s PSB file shows a citation for missing court later that month.
The court filing also described problems that arose during DiPonzio’s tenure in the child sex crimes unit. According to court documents, DiPonzio was reported by her supervisor for failing to interview victims identified in child sex crime investigations for two months.
In 2013, DiPonzio canceled interviews of victims due to illness. She tried to contact them two more times the next week. She did not attempt again until two months later, when she also learned that the alleged assailant was in the home. The allegation was sustained and DiPonzio received “coaching.”
Despite the Professional Standards Bureau substantiating these allegations and disciplining DiPonzio, she never appeared on the county attorney's Brady List. And still doesn't.
Where this started: A deadly drive-by
On June 7, 2020, Lawrence Hunter was waiting by the car while his wife ran into the Family Market at 15th and Cocopah streets. In the parking lot, he recognized a cousin whom he hadn't seen in 20 years.
Hunter and his cousin spoke and took photos together. Then Hunter and his wife, Angela Crister, left in their black Chevy Tahoe. Crister drove. As they headed down South 15th Street, gunfire rang out and struck their car from behind.
Hunter returned fire before realizing that his wife had been shot. He stopped the car, pushed her into the passenger seat and started driving to the hospital. On the way, he saw police and flagged them down.
Crister died from her injuries.
In the immediate aftermath, Hunter identified the shooter as his paternal cousin, Anthony Vaughn. But during further police questioning, Hunter said that he had mixed up the names of his cousins and that the shooter was actually Anthony’s brother, the defendant, Eddie Vaughn.
Hunter also recalled Eddie Vaughn pointing a gun at him in the Family Market parking lot.
DiPonzio first showed Hunter a photo of Anthony Lee Vaughn, whom Hunter said was not the shooter. When DiPonzio showed him a photo of Eddie Vaughn, Hunter identified him as the shooter.
Defense lawyers later discovered DiPonzio had shown Hunter a photo of the wrong Anthony Vaughn ― Hunter’s cousin’s full name is Anthony Ray Vaughn.
According to court documents, police typically show witnesses a six-person photo lineup. Vaughn's lawyers argued that using a single photo was suggestive and could have led Hunter to make a false identification. The court ultimately ruled that it was allowable because a single-photo identification is typical when the witness knows the suspect, even if they had not seen each other in years.
Vaughn was indicted on an aggravated assault charge on June 18, 2020.
Prosecutors claimed that while he was in custody, Vaughn asked his former attorney to send police reports of the shooting to his then-girlfriend. His girlfriend reportedly passed the documents onto Marcus Allen, whom prosecutors described as being gang-affiliated. Prosecutors said that in jail calls, Vaughn expressed a desire to seek out “street retribution” for a witness who was cooperating with the state.
Both Vaughn’s then-girlfriend and Allen were charged with assisting a street gang and entered into plea agreements. According to court documents, prosecutors expect Allen to testify in Vaughn’s homicide case.
On Sept. 8, 2021, Vaughn was charged with additional counts of first-degree murder and drive-by shooting.
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Despite DePonzio's absence, allegations against her have come to play a major role in Vaughn’s case.
Le Lievre said that he had attempted to interview DiPonzio several times in 2022.
When DiPonzio was continuously unavailable, Le Lievre filed an August 2022 motion to compel her to testify, or force prosecutors to share information related to her leave.
Le Lievre argued the personnel documents were key because “there is a high probability they pertain to her ability to perceive, recollect, or relay accurately.”
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In court documents, the Maricopa County Attorney’s Office said that Le Lievre’s motion prompted them to ask Phoenix police for more information about DiPonzio’s leave. It was then, prosecutors said, that they were notified that DiPonzio had left the force due to a medical condition that made her unavailable to testify as a witness in the trial.
In November 2022, two years into the prosecution, the court inquired whether DiPonzio was on the Brady List, court records show.
In a court filing, prosecutors claimed that prior to Nov. 17, they had no record of DiPonzio ever having been referred to their office for Brady List consideration.
The County Attorney's Office provided The Arizona Republic with a copy of a letter sent quarterly to law enforcement agencies requesting that they share "adverse investigative findings in personnel investigations" that have to do with the credibility of officers.
The letter lists examples of pertinent conduct, which includes incompetence and mishandling evidence.
Because of the court's inquiry into the Brady List, Deputy County Attorney Ryan Green asked the office’s law enforcement liaison, Tom Van Dorn, to reach out to the Phoenix Police’s Professional Standards Bureau.
In an email on Nov. 17, Van Dorn told prosecutors that there was an open PSB investigation into DiPonzio, which “wasn’t able to move forward” because of her medical status.
Court records show that prosecutors notified the defense team of the PSB investigation the same day.
According to court documents, prosecutors then requested materials relating to the open PSB investigation, which they said involved a series of recordings that DiPonzio did not properly catalog. This included three recordings that were associated with the Vaughn case, which prosecutors described as relating to contacting next of kin and following up with a witness.
The recordings were disclosed to defense lawyers in December 2022. In a court filing, prosecutors wrote, “Through an oversight, the police report documenting the association of these recordings was not disclosed until April of 2023.”
Prosecutors said that in April, defense lawyers were shown the remaining recordings and photos of DiPonzio's desk.
At the March hearing, Valenzuela, who is also the assistant bureau chief of the Capital Litigation Unit, said, “We are not covering up anything. We are not trying to conceal anything.”
Le Lievre countered that, during the case against Eddie Vaughn, prosecutors had not been forthcoming about their knowledge of DiPonzio’s professional conduct.
“This information did not come to light because of the altruistic tendencies of the state in this case. It only came to light through consistent, relentless litigation,” Le Lievre said.
"The Department has been continuously working with the Maricopa County Attorney's Office to provide information and bring these cases to resolution. The Phoenix Police Department remains committed to providing the highest level of public safety and supporting victims of crime in pursuing justice," Rossi, the Phoenix police spokesperson, told The Republic.
On July 6, Le Lievre filed a motion to compel an interview of the Professional Standards Bureau investigator Sgt. Allison Steinberger. During a July 31 hearing, Judge Bruce Cohen granted it.
But Cohen expressed concern that the case would develop into “a trial within a trial” of DiPonzio, who would never testify and cautioned Le Lievre not to chase DiPonzio down a “rabbit hole.”
Lievre also said during the hearing that he planned to file two motions to dismiss the case against Vaughn.
Vaughn's next hearing is Aug. 18.
This article originally appeared on Arizona Republic: Allegations against Phoenix police detective could influence 37 cases
