amphotora/iStockBy BILL HUTCHINSON, ABC News(ST. LOUIS) — A retired St. Louis police captain who became a small-town police chief was found fatally shot early Tuesday outside a pawn shop that was looted after protests over the death of George Floyd turned violent.David Dorn, 77, was discovered on the sidewalk in front of Lee’s Pawn & Jewelry in St. Louis around 2:30 a.m., said Police Commissioner John Hayden. He said Dorn, who retired from the St. Louis Police Department in 2007 and had been serving as police chief of Moline Acres, Missouri, since 2008, was killed when he apparently tried to stop the looting of the shop.“David Dorn was exercising law enforcement training that he learned here,” Hayden said. No further details were immediately released.His widow, Ann Marie Dorn, told the St. Louis Post-Dispatch that her husband was a friend of the pawn shop’s owner and frequently checked on the business when alarms went off.The death came on a brutal night for police across the country.A Las Vegas police officer on life support was last listed in critical condition after being shot Monday night attempting to disperse a large crowd of protesters outside a casino, authorities said.An officer was attacked in New York City, and four cops were shot in St. Louis as demonstrations across the nation in the aftermath of George Floyd’s death have turned increasingly violent for both protestors and police.At least five deaths have occurred during the widespread unrest, according to The New York Times.The Las Vegas Metropolitan Police Department officer was critically wounded engaging with violent protesters outside the Circus Circus Hotel & Casino on the famed Las Vegas Strip. Separately, police fatally shot a heavily armed man who appeared to be wearing body armor outside a federal courthouse nearby.“This is a sad night for LVMPD family and a tragic night for our community,” LVMPD Sheriff Joe Lombardo said at a news conference. “With these protests, which are leading to riots, one tragedy is only leading to another.”Lombardo said his officers were being pelted with rocks and bottles.“Our officers were attempting to get some of the protesters in custody when a shot rang out and our officer went down,” he added.The wounded officer was taken to Las Vegas University Medical Center, where he was in “extremely critical condition.”A suspect was arrested by a SWAT team, but that person’s name wasn’t immediately released, Lombardo added.While LVMPD officers were investigating the shooting, officers guarding the Foley Federal Building were confronted by an armed man around 11:22 p.m., Lombardo said. That suspect, who appeared to be wearing body armor, had multiple firearms.“During the interaction, the subject reached for his firearm and our officers engaged him,” Lombardo said. The suspect, who hasn’t yet been identified, died at the hospital. It’s unclear whether that individual had been among the protestors, Lombardo added.The four officers wounded in St. Louis on Monday night were shot near police headquarters, where clashes with rioters lasted well into the night.“They were standing near a line and all of a sudden they felt pain,” Police Commissioner Hayden said during a news conference Tuesday morning. “They were just standing there. So some coward fired shots at officers, and now we have four in the hospital … and thank God they’re alive. Can we make some sense out of this? … This is horrible.”The officers, ranging in age from 28 to 52, suffered non-life-threatening injuries. Before the shootings, demonstrators hurled rocks and fireworks at police, and some officers had gasoline dumped on them, Hayden added.Meanwhile in New York City, video emerged that appeared to show an officer being attacked with a heavy object by a group of men in the Bronx. The New York Police Department said it made nearly 700 arrests Monday night as looting and vandalism targets included stores at Rockefeller Center and some in the Upper East Side. A curfew of 11 p.m. had been put in effect.“We saw stuff last night that we will not accept. And we can fight back, and we will fight back,” Mayor Bill de Blasio said at a news conference on Tuesday. “I have confidence in the people of New York City, I have confidence in the leaders in communities, I have confidence in the NYPD.”“There’s a lot of people trying to express fear, a lot of people trying to tear down, a lot of people say they don’t believe in the people of this city, they don’t believe in people in our communities, they don’t believe in our police officers. To hell with all of them. I don’t care if they’re left or right or center — I am sick of people attacking New York City,” he continued.Floyd died May 25 in Minneapolis. His final moments were captured in a searing video of a white officer with his knee on Floyd’s black neck as he pleaded for his life. “I can’t breathe,” Floyd said.Copyright © 2020, ABC Audio. All rights reserved.