The police department in Madison, Wisconsin, and federal prosecutors said they were closing a monthslong investigation due to lack of evidence into an alleged hate crime against a biracial woman who said she was set on fire by a group of white men.
The Madison Police Department began investigating after Althea Bernstein, 18, told police in June that four white men yelled a racial slur at her through her rolled-down car window while she was stopped at a traffic light around 1 a.m.
She said one of the men then used a spray bottle to douse her with a liquid and threw a flaming lighter at her, according to a police department incident report. Bernstein said the liquid ignited, burning parts of her face and neck.
The U.S. attorney’s office in Madison said Friday that after a "thorough investigation" into the incident, it was closing the case without charges filed.
"Federal investigators determined that there is insufficient evidence to prove that a violation of any federal criminal statute occurred," the office said in a statement. "Further, after reviewing all available evidence, authorities could not establish that the attack, as alleged by the complainant, had occurred."
Madison Acting Police Chief Vic Wahl also issued a statement saying that "detectives were unable to corroborate or locate evidence consistent with what was reported."
"Detectives conducted numerous interviews, reviewed extensive video, and analyzed physical/digital evidence during the course of the investigation," Wahl said.
A spokesman for the Bernstein family told NBC News in June that the teen was driving to a friend's house when the men started yelling the N-word and then set her on fire. She was able to pat out the flames, the spokesman said.
Photos released at the time showed injuries to Bernstein's face and neck.
Madison police released nearly 160 pages of reports detailing its investigation into the incident. Surveillance video from traffic and surveillance cameras shows that Bernstein's car only stopped once and that no other vehicle or person was around the car.
Investigators could not find a group of white men on the cameras, according to the reports.
The documents released by police also showed that the car Bernstein was driving had not been damaged during the alleged incident and that an arson dog found no trace of a lighter or other device used to ignite a fire. Medical records, however, showed that she was treated for burns on the day she said the attack happened.
Bernstein was told in August that investigators could not find evidence to corroborate her account, the reports show. The teen told a detective that she didn't understand why there was no evidence and said she was "100% confident of what happened."
During a meeting last week with Bernstein's attorney, Andrea Sumpter, an investigator said that there were no plans to charge Bernstein. The reports stated that investigators "found no evidence that Bernstein had colluded with anyone to make a false report or that there was any mal-intent or pre-planning that occurred in regards to Bernstein's statement to police."
"I acknowledged to Attorney Sumpter that clearly Bernstein had injuries to her face. I explained to Attorney Sumpter that our interests at this point were identifying if there was someone else responsible for causing these injuries to Bernstein," the documents state. "If so, our goal was to hold this person responsible."
Sumpter could not immediately be reached by NBC News on Tuesday. Bernstein's family issued a statement through the police department thanking the detectives and investigators for their work.
"Althea's injuries are healing and the support of our community has been invaluable in that regard. We continue to maintain our family privacy and will not be granting interviews at this time," the family said.