The commissioner tweeted that Simonsen was a 19-year veteran of the department.
Sen. Chuck Schumer said, "We are forever indebted to the courageous NYPD detective who was killed in Queens tonight and the sergeant who was wounded".
De Blasio on Tuesday night praised officers for rushing into risky situations and taking decisive action when lives are threatened.
A New York Police Department detective was shot and killed Tuesday, and a sergeant was hit in the leg, after they responded to a reported robbery at a cell phone store in the borough of Queens, city officials said.
Police Commissioner James O'Neil said the death was "an absolute tragic case of friendly fire" in a press conference at Jamaica Hospital Medical Center, adding that the suspect was "carrying an imitation firearm".More news: Police ask woman who threw chair from balcony to surrender
"Shots fired! Shots fired!" an officer is heard yelling on the dispatch audio over a barrage of gunshots.
"Shots fired! Shots fired!" an officer is heard yelling. Another NYPD officer was wounded during the incident and was rushed to the hospital along with Simonsen where he was pronounced dead.
Mayor Bill de Blasio is at the hospital.
O'Neill said as the suspect advanced toward them, the officers discharged their weapons and retreated out of the store.
"No sirens, guys", the dispatcher warns.More news: OnePlus’ 5G prototype smartphone will be shown off at MWC
Arwin Singh, a 31-year-old construction contractor who lives across from the T-Mobile store, told the outlet: 'I looked out and the cops were running into [the store] to get them. Simonsen and the sergeant arrived at the scene at the same time as patrol units. Some walked together in a line, searching for evidence.
Senate Democratic Leader Chuck Schumer tweeted condolences. Chuck Schumer D-N.Y. tweeted: "We are forever indebted to the fearless NYPD detective who was killed in Queens tonight and the sergeant who was wounded. May God bless them and their families".
New York Attorney General Letitia James said it was "a painful night for all of New York City".
"It was heartbreaking, absolutely heartbreaking", De Blasio said.
Before Tuesday, eight U.S. police officers had been killed by firearms while on duty in 2019, according to the National Law Enforcement Officers Memorial Fund website.More news: Ole Gunnar Solskjaer: Manchester United not dead in Europe despite PSG defeat
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