A list of mass killings in the United States this year

The latest mass killing in the U.S. happened in Ferguson, Missouri, where authorities say a 39-year-old woman intentionally set a fire at home to kill herself and her four children.

The children were 9-year-old twins, a 5-year-old and a 2-year-old. Police announced late Wednesday that a preliminary investigation determined it was a murder-suicide. Investigators believe the mother set fire to a mattress, and a note was left stating her intentions to kill herself and her children, police said.

Responding firefighters found the home engulfed in flames at 4:23 a.m. Monday. Neighbors had tried to save the family, but the fire was too intense.

The woman and the two fathers of her children were involved in prolonged legal disputes over the kids, according to a statement issued on behalf of her relatives by her attorney. She had been happy and enjoyed life and was a loving mother, but those court battles brought her to a moment of crisis that resulted in tragic consequences, the statement said.

This was the country’s 9th mass killing this year, according to a database maintained by The Associated Press and USA Today in partnership with Northeastern University.

Less than two months into the new year, at least 43 people have died in those killings, which are defined as incidents in which four or more people die within a 24-hour period, not including the killer — the same definition used by the FBI.

The nation is witnessing the third-highest number on record of deaths due to mass killings by this point in a single year. Only 2023 and 2008 saw more deaths from mass killings at this point, with 53 deaths and 47 deaths, respectively. Last year ended with 42 mass killings and 217 deaths, making it one of the deadliest years on record.

According to the database as of Friday, there have been 583 mass killings since 2006, in which 3,032 people died and 2,040 people were injured.

Here’s what happened in the other U.S. mass killings this year:

BIRMINGHAM, ALABAMA: Feb. 16

Officials said four men are dead following a drive-by shooting in a neighborhood. Dozens of shots were fired outside a Birmingham home, police said. A group had been standing outside of a house as people got their cars washed when someone drove by and opened fire. Investigators said they believe at least one of the victims was targeted. No arrests were immediately reported.

HUNTINGTON PARK, CALIFORNIA: Feb. 11

Shootings over several hours killed four people: a man in Bell, a man in a Los Angeles shopping center parking lot, a 14-year-old boy in Cudahy, and a homeless man in Huntington Park, authorities said. At least one other juvenile was wounded. Authorities arrested two men, ages 42 and 20, in connection with the shootings. They are suspected of being gang members, officials said. A motive was not immediately identified, but investigators said they believe the victims were randomly targeted.

EAST LANSDOWNE, PENNSYLVANIA: Feb. 7

Six sets of human remains were recovered from the ashes of a fire that destroyed a home about 5 miles (8 kilometers) from Philadelphia, according to the county district attorney's office. Authorities suspect the family members who died — including three children — were killed by a 43-year-old male relative who also died after shooting and wounding two police officers, the office added. A motive was not immediately identified.

EL MIRAGE, CALIFORNIA: Jan. 23

Authorities found the bodies of six men in the Mojave Desert outside the sparsely populated community of El Mirage after someone called 911 and said he had been shot, according to sheriff’s officials. The men were likely shot to death in a dispute over marijuana, local authorities said. The bodies were found about 50 miles (80 kilometers) northeast of Los Angeles in an area known for illegal cannabis operations. Five men suspected in the violence were arrested and charged with murder. All pleaded not guilty.

JOLIET, ILLINOIS: Jan. 21

A 23-year-old man is suspected of fatally shooting eight people — including seven of his relatives — and injuring a ninth person in a Chicago suburb. He fatally shot himself later during a confrontation with law enforcement in Texas. Authorities said they believe he was trying to reach Mexico. Police said the victims included his mother, siblings, aunt, uncle and two men he might not have known. They were found in two homes, outside an apartment building and on a residential street.

TINLEY PARK, ILLINOIS: Jan. 21

A 63-year-old man in suburban Chicago is accused of killing his wife and three adult daughters in what police have described as a domestic-related shooting. Police allege he shot the four family members – ages 53, 24 and two 25-year-old twins – after an argument at their home. He was charged with four counts of first-degree murder, according to authorities.

RICHMOND, TEXAS: Jan. 13

A 46-year-old man fatally shot his estranged wife and three other relatives, including his 8-year-old niece, at a home in suburban Houston before killing himself, authorities said. The man opened fire at the home just before 7 a.m. that Saturday after returning his young child from a visit. Authorities said that after arriving at the home, he told his estranged wife that he wanted to reunite, but she refused. In addition to killing his niece and estranged wife, he also killed her brother and sister, ages 43 and 46.

REEDLEY, CALIFORNIA: Jan. 6

A 17-year-old boy was charged with killing four members of a neighboring family in central California. He lived next door to the victims – ages 81, 61, 44 and 43 – in Reedley, a small town near Fresno. The bodies were found on Jan. 6 in the backyard of their home, including one buried in a shallow grave, and in the detached garage of the teenager’s home, police said.