BBC News wrote:An armed officer who stood outside a Florida school where a gunman killed 17 people last week "certainly did a poor job", US President Donald Trump says.
Deputy Scot Peterson resigned after an investigation found he failed to confront the suspect.
Mr Trump said Mr Peterson might be a "coward" who "didn't react properly under pressure".
Florida's governor meanwhile called for law enforcement officers to be placed in every public school in the state.
What did Trump say?
Speaking on Friday at the Conservative Political Action Conference (Cpac) in Maryland, Mr Trump touted his love for gun rights.
He again proposed arming teachers as a solution to school safety, a method long championed by the National Rifle Association (NRA) gun lobby.
Speaking to reporters outside the White House earlier, Mr Trump criticised the police officer who did not confront the perpetrator of the 14 February massacre in Parkland, Florida.
"He trained his whole life but when it came time to do something he didn't have the courage," the Republican president said.
"He certainly did a poor job."
"But that's a case where somebody was outside, they're trained, they didn't react properly under pressure or they were coward," he added.
Trump, calling someone else a coward. Pot, kettle.