ST. LOUIS (AP) — A retired St. Louis police captain killed by people who broke into a pawn shop after protests turned violent was a gregarious and outspoken leader who mentored youths and insisted on strict ethical conduct among his employees, a longtime colleague said Tuesday.

David Dorn, 77, was found dead on the sidewalk in front of Lee’s Pawn & Jewelry about 2:30 a.m. Tuesday. No arrests have been made.

The shooting and theft apparently was posted on Facebook Live, but the video has since been taken down. It came on a violent night in St. Louis, where four officers were shot, officers were pelted with rocks and fireworks, and 55 businesses were burglarized or damaged, including a convenience store that burned. Police also shot and gravely injured a burglary suspect who they say shot at officers.

Cities across the U.S. have seen protests and violence since George Floyd died May 25 after a white Minneapolis officer pressed his knee into Floyd’s neck for several minutes even after the handcuffed black man stopped moving and pleading for air.

Dorn, who was black, was a friend of the pawn shop’s owner and frequently checked on the business when alarms went off, his wife, St. Louis police Sgt. Ann Marie Dorn, told the St. Louis Post-Dispatch.

David Dorn served 38 years on the St. Louis police force before retiring in October 2007. He then became chief of Moline Acres, a small town in St. Louis County.

Former St. Louis County police Chief Tim Fitch knew Dorn for 30 years and said they became close friends when Dorn and his wife were leading the St. Louis police department’s Explorers program for young people interested in law enforcement careers, while Fitch was leading the county’s program.

“He was very dedicated to youth, especially disadvantaged youth,” said Fitch, who led the St. Louis County Police Department from 2009 to 2014. “He wanted to see them succeed. He wanted to be a role model for those young men and women to go into law enforcement.”

Dorn’ s personality was “bigger than life,” Fitch said. “He was a fun guy, a happy guy. You never had to wonder what he was thinking when somebody did something incredibly stupid like a crime because he would just say it as he saw it.”

When he took over as chief in Moline Acres, Dorn made it clear that his officers would be held to the strictest of standards, Fitch said.

“He wanted them to do the right thing all the time,” Fitch said.

The Ethical Society of Police, which represents black officers in St. Louis, said in a news release that Dorn was “the type of brother that would’ve given his life to save them if he had to.”

St. Louis police Chief John Hayden called Dorn a “fine captain.”

“Many of us, the other officers, looked up to him,” Hayden said. “Was very well-liked, very pleasant. And his wife still works here. So a very sad time for our agency. We will honor him.”