Only days after thousands of grieving Parkland students and families gave him a standing ovation on national television, Scott Israel suddenly finds himself embroiled in controversy over his agency's response to the worst high school shooting in U.S. history.

Cheers from the students at Marjory Stoneman Douglas High School have been drowned out by demands from dozens of state lawmakers that he be suspended from office for "incompetence and neglect of duty." Queries about acts of heroism have been replaced by a state investigation into why one of his deputies waited while teenage gunman Nikolas Cruz killed 17 and wounded 15 more with an assault rifle.

Somehow, the worst stretch of Scott Israel's life has gotten even worse.

"The failures of Sheriff Israel and his deputies during and after the horrific shooting at Marjory Stoneman Douglas High School on February 14, 2018, and their failures to intervene regarding Nikolas Jacob Cruz in the years, months, and days leading up to that shooting, are unacceptable and unforgivable," Florida House Speaker Richard Corcoran wrote Sunday in a letter to the governor signed by dozens of House Republicans. "As a result of Sheriff Israel's failures, students and teachers died."

The letter, along with news from Gov. Rick Scott that the Florida Department of Law Enforcement had decided Sunday to investigate the Broward Sheriff's Office's handling of the shooting, reflect a dramatic reversal of fortune for Israel, arguably Broward County's most powerful elected official.

In the days after the shooting, Israel was a face of calm, a rock defending a neighborhood where he coached football, his triplets attended school and until recently he owned a home literally across the street from Stoneman Douglas High School. An advocate for the ban of semi-automatic assault rifles, the Democratic cop successfully lobbied Florida's NRA-backed, Republican governor to promote mental health legislation and acted as an amplifier for a community that has reignited a national movement for gun control.

And now? Instead of wielding a bullhorn or advocating from a microphone, Israel is under a spotlight. The conversation has shifted away from gun control and toward his agency's response to the shooting, and whether BSO could and should have done more.

"I have asked for FDLE to immediately investigate the law enforcement response and will continue to review this matter as more facts come out," Scott said Sunday in a statement that suggested he'll wait to decide whether to suspend the sheriff until all facts are out. "That's what the victims and their families deserve."

Israel, suddenly the perfect foil for an NRA that blames blown investigations and mental health, remains defiant.

Attempts to reach the sheriff for this article were unsuccessful. But he said through a statement Sunday that he welcomes an outside review of his response to the Valentine's Day shooting and his agency's reaction to what BSO has identified as 23 tips and calls for service to Cruz's homes, none of which, BSO says, were for arrestable offenses. Israel even boasted on CNN about his role in the aftermath.

"I can only take responsibility for what I knew about. I exercised my due diligence. I've given amazing leadership to this agency," he said. "Deputies make mistakes. Police officers make mistakes. We all make mistakes. But it's not the responsibility of the general or the president if you have a deserter."

Israel, 61, dismissed second-guessing of his department.

"If ifs and buts were candy and nuts, O.J. Simpson would still be in the record books."

The sheriff, who before leading BSO served for decades as a Fort Lauderdale detective and then police chief of North Bay Village, has been dogged by turmoil before. But not like this.

He took heat for hiring political allies and childhood chums after becoming sheriff in 2012 and for failing to report that a campaign booster paid for a yacht cruise and party after his first election. After Esteban Santiago shot up Terminal 2 at the Fort Lauderdale-Hollywood International Airport, Israel's own department found that law enforcement caught the shooter in seconds but had led a half-confused response that bogged down the airport for hours.

But this is different. This isn't just political, it's also personal.

Israel has incredibly close ties to the school. While Deputy Scot Peterson waited outside the freshman building as Cruz killed 14 students and three faculty, Israel's personal friend, Aaron Feis, rushed inside to stop the shooter and died trying.

"I know Scott. I know his family. I'm sure this is something that's eating him up. He knows this community inside and out," said county commissioner and former Parkland Mayor Michael Udine, who has been infuriated by revelations of ignored law enforcement tips about Cruz. "I'm past the point of sorrow. I'm to the point of anger."

And it's a national saga.

On Wednesday, when CNN invited Israel on stage at the BB&T Center to take questions from Stoneman Douglas students and teachers, an estimated 3 million people watched as students who lost friends and parents who lost children excoriated U.S. Senator Marco Rubio for declining to agree to reject the National Rifle Association as a political backer. The FBI, which declined to attend, was hit with a pre-written question by a math teacher about why it failed to react to a tip in January that Cruz was planning to shoot up his former school.

Asked generally about his agency's handling of calls regarding Cruz, Israel said lawmakers needed to change the laws to give police more power to take mentally ill persons into custody and keep them away from guns. He wasn't hammered because the details hadn't come out yet.

It wasn't until the next day that Israel announced that armed school resource officer Scot Peterson had waited for "upwards of four minutes" outside the freshman building while Cruz did his killing, and that five times during the last year BSO had received tips that included information that Cruz was either suicidal, obsessed with guns or planning to shoot up a school.

In November, a Massachusetts woman who reported that Cruz was a "school shooter in the making" was referred to the Palm Beach County Sheriff's Office because Cruz was living in Lake Worth. No report was documented by BSO.

"This could've come out much sooner," said former Broward sheriff Al Lamberti, who lost the 2012 election to Israel, about the details of BSO's problematic response. "And it would have been nice to have this information before the president of the United States showed up to thank everybody for what they did. It would have been nice to have this information before CNN showed up."

On CNN on Sunday, Israel said he waited to disclose his agency's findings until Thursday because he needed to confirm all the details and conclusions. He also said he wanted his detectives to call the families of the victims, rather than force them to learn such troubling details on national television along with the rest of the country.

"I'm not on a time line for TV or any news show," said Israel, who said he hadn't seen video of Peterson's response until Thursday. "I certainly wouldn't disclose that to a family at a town hall."

Israel also divulged new details about BSO's response to the shooting over the weekend, writing in a letter to Gov. Scott that Peterson had received active shooter training. He confirmed Sunday that Coral Springs police were the first to enter the school, and that they found more deputies waiting outside when they arrived. But he said the deputies may have been acting on incorrect information from Peterson that he had eyes on Cruz and they needed to establish a perimeter.

At that point, he said, Cruz's attack was already over.

"We don't know what those deputies heard," he said.

Israel says his department, which has a budget approaching $500 million and thousands of employees, is conducting its own investigation and taking hundreds of statements but remains focused on the prosecution of Cruz.

What may matter most to Israel politically in the coming days and weeks is whether he continues to have support from Democrats, and most importantly — and personally — from Parkland. Jared Moskowitz, a Stoneman Douglas alum and the state representative from Parkland, called Peterson's dereliction of duty "reprehensible and unforgivable" after learning about his failure to try and stop Cruz. But he said in an interview Friday that he would focus on legislation and allow investigations to run their course.

Israel also disputed Sunday that Coral Springs' city manager had reamed him out in front of grieving families after a Feb. 15 vigil, calling it "just two guys having a conversation." A source told the Miami Herald that the sheriff's office met Friday with Coral Springs police to discuss the response.

Students have so far remained positive, keeping their focus on the weapons Cruz was able to purchase as a 19-year-old with a history of mental illness, and not whether a deputy didn't try to stop the shooting once it started.

"When [NRA spokeswoman] Dana Loesch was going at Scott Israel in the town hall, a lot of people were really upset about the fact that she was laying into him like that, saying that it was his fault, that this should have been prevented because of him. That's not true," said Emma González, a student whose "BS" speech went viral. "This tragedy would not have been nearly as bad if these guns had not been involved in the first place."

On Sunday, Israel said the facts will come out after an investigation, and then Parkland will have justice.

"We understand everything wasn't done perfectly," he said. "Do I believe had Scot Peterson had went into that building there was a chance he could have neutralized the killer and saved lives? Yes I believe that. But as far as anything else done at this point, I can't say that."

Miami Herald staff writers Nicholas Nehamas and Martin Vassolo contributed to this report.