State Rep. Bill Hager, a Republican lawmaker from Boca Raton, called on Gov. Rick Scott to remove Broward County Sheriff Scott Israel from office because of the missed red flags before the Parkland school shooting.
Israel vowed not to resign, saying Hager's letter "was full of misinformation" and "shameful, politically motivated."
Earlier Sunday, Florida Gov. Rick Scott's office said he had asked Florida Department of Law Enforcement Commissioner Rick Swearingen to investigate the law enforcement response to the shooting. The agency confirmed it would begin the probe immediately.
Israel has come under withering scrutiny after the revelation last week that deputy Scot Peterson, the school's assigned security officer, was nearby when the shooting began but did not go into the building to confront Cruz during the attack.
The sheriff's office is also facing a backlash for apparently mishandling some of the 18 tipster calls related to the suspected shooter. The tips were among a series of what authorities now describe as the clearest missed warning signs that Cruz, who had a history of disturbing behavior, posed a serious threat.
Israel defended his leadership Sunday and said investigators were looking into claims that three other deputies were on the scene but failed to enter the school when the chance to save lives still existed. To date, the investigation has pointed to only one deputy being on school grounds while the killer was present, he told CNN.
Israel also labeled as "absolutely untrue" reports that the deputies waited outside even though children were inside the building needing urgent medical treatment.
House Speaker Richard Corcoran stepped up the pressure Sunday, calling on Scott to suspend the sheriff.
"In the years leading up to this unspeakable tragedy, Sheriff Israel, his deputies, and staff ignored repeated warning signs about the violent, erratic, threatening and antisocial behavior of Nikolas Jacob Cruz," Corcoran said in a letter signed by more than 70 lawmakers.
Scott said in a statement Sunday that he understands Corcoran's concerns, but added "there must be an independent investigation."
"Like me, he wants the families to have answers and for there to be full accountability. That's what the victims and their families deserve," Scott said.
Israel insisted that lapses were being investigated. He told CNN that a deputy who responded to a Nov. 30 call referring to Cruz as a "school shooter in the making" was being investigated by internal affairs for not filing a report and had been placed on restrictive duty.
"There needed to be report. And that's what we are looking into— that a report needed to be completed, it needed to be forwarded to either Homeland Security or a violent crimes unit," Israel said.
The FBI has acknowledged that it failed to investigate the tip about Cruz that the agency received on Jan. 5.