Four people were killed and 17 others injured in a mass shooting late Saturday night in Birmingham, Alabama, when multiple gunmen opened fire in a busy entertainment district. The shooting, which took place in the Five Points South area, is believed to have been a targeted attack on one individual, with the remaining victims caught in the crossfire, police said. “Someone was willing to pay money to have that person killed,” Birmingham Police Chief Scott Thurmond said at a news conference on Sunday.

The gunmen arrived in a vehicle just after 11 p.m., opened fire, and then fled the scene, according to police. The attack, which left more than 100 shell casings scattered across the area, killed two men and a woman at the scene, while a fourth man died later at a hospital. The Birmingham Police Department, working with the FBI, is urging anyone with information to come forward as the shooters remain at large. Investigators suspect that illegal gun conversion devices, which can turn semi-automatic weapons into fully automatic firearms, may have been used.

Birmingham Mayor Randall Woodfin described the city’s gun violence as being at “epidemic levels” and called for stricter laws to combat the issue. He specifically pointed to the use of conversion devices, which are federally illegal but not regulated at the state level. The mayor said enforcement requires a political shift, noting that stronger laws are needed to give police “the tools to take shooters off the streets prior to an incident like this.”

The shooting took place in one of Birmingham’s liveliest neighborhoods, known for its bars, restaurants, and live music venues. Witnesses described a scene of chaos as emergency responders worked to transport victims to hospitals. One bystander, Dajon Singleton, told a local news affiliate that he heard screams and watched as several victims were taken away on stretchers. “It was very devastating,” Singleton said, adding that crime in the area typically spikes around the holidays.

As of Sunday evening, four of the surviving victims were reported to be in life-threatening condition. The shooting is part of a larger trend of escalating gun violence in Birmingham, which has seen an increase in homicides this year despite national declines. “Rest assured, we are going to do everything we possibly can to uncover, identify, and hunt down who was ever responsible,” Officer Truman Fitzgerald said. Local businesses have been asked to provide any surveillance footage that could aid in the investigation.