Law enforcement officers with an arrest warrant demanded that a man come out of a house in North Carolina before four were killed by gunfire, the victims unable to survive shots coming from inside the dwelling, a witness and officials said Tuesday.

Still reeling from Monday’s attack — the deadliest against U.S. law enforcement officers since 2016 — investigators in Charlotte said they weren’t sure whether there was a second shooter and that more work was needed to determine what happened.

“Charlotte isn’t going to be the last place that this happens,” Mayor Vi Lyles said, “but Charlotte will be the place that will heal — that will heal with dignity and respect for everyone.”

A task force made up of officers from different agencies had arrived in the suburban neighborhood to try to capture Terry Clark Hughes Jr., 39, who was wanted for possession of a firearm by an ex-felon and fleeing to elude in Lincoln County, North Carolina.

Those killed were identified as Sam Poloche and William Elliott of the North Carolina Department of Adult Corrections; Charlotte-Mecklenburg Officer Joshua Eyer; and Deputy U.S. Marshal Thomas Weeks. Four other officers were wounded in the shootout, and Hughes was also killed.

An AR-15 semi-automatic rifle, a 40-caliber handgun and ammunition were found at the scene.

An AR-15 is able to penetrate traditional body armor and allowed the shooter to “unload several rounds towards our officers within a matter of seconds,” said Charlotte-Mecklenburg Police Chief Johnny Jennings.

He said more than 100 spent rounds were found, though it wasn’t clear how many were fired by the suspect. At least 12 officers also fired guns.

“Even though officers were trying to take cover, they were at a disadvantage because the suspect was up at a higher level and they were returning fire from a lower position,” Jennings said, noting that the gunman was “shooting from upstairs.”

It was the deadliest day for U.S. law enforcement in one incident since five officers were killed by a sniper during a protest in Dallas in 2016.

Hughes’ criminal record in North Carolina goes back more than a decade. It includes prison time and convictions for breaking and entering, reckless driving, eluding arrest and illegally possessing a gun as a former felon, according to state records.

Saing Chhoeun, who lives next door, recalled hearing several demands that Hughes leave the home. There was no response, he said, but then a car alarm went off about the same time as gunfire.

He said an armored vehicle was subsequently parked between the house and the wounded officers to serve as protection during a rescue attempt. After a three-hour standoff, the home was torn open by specialty vehicles.

“I don’t know how many rounds were fired. But then it got quiet,” Chhoeun told The Associated Press.

Two females who were inside the house, including a minor, were cooperating and have not been charged, the police chief said, adding that investigators weren’t pursuing additional suspects.

Jennings said Monday that a second shooter was suspected of firing at police. But by Tuesday, he was backing off and said that possibility was still being checked.

Before taking questions from reporters, officials expressed sorrow and awe for the slain and wounded officers.

Eyer was recently honored as a Charlotte-Mecklenburg officer of the month, partly for working to get guns off the streets. Jennings said he was killed while responding to others who were facing gunfire at the scene.

“We saw … officers going into the line of fire to save their brothers in blue, who have gone down in the act of trying to keep our community safe,” Jennings said. “To me, that’s truly heroic.”

Residents in the neighborhood of modest brick homes expressed fear a day later.

“We’ve been here such a long time — you raise your children here — and then all the sudden you have this tragedy,” said Yearly Washington, who has lived there for 35 years.

The last marshal killed in the line of duty was in November 2018. Chase White was shot in Tucson, Arizona, by a man wanted for stalking local law enforcement.

The Carolinas Regional Fugitive Task Force, headquartered in Charlotte, is comprised of 70 federal, state and local agencies collaborating to capture crime suspects.

“This is a loss for the entire country,” said Marshals Service Director Ronald Davis, who traveled to Charlotte. “Losing a deputy, losing task force officers, is like losing a family member because, quite frankly, they are family members.”

(AP)