During hours-long grilling by lawmakers on Capitol Hill, law enforcement officials provided new details on critical warning signs and owned up to potentially causing grave mistakes after not following through on tips that could have intervened in a deadly mass shooting in Parkland, Florida last month.

Officials from the ATF, FBI and Secret Service provided their testimony to the Senate Judiciary Committee on Wednesday into apparent failures across local and federal law enforcement agencies in investigating the accused shooter Nikolas Cruz from opening fire at Marjory Stoneman Douglas High School and killing 17 people last month.

The FBI has already apologized for failing to act on a tip last month from a person who was concerned that Cruz could shoot up a school, but acting deputy director of the FBI David Bowdich acknlowedged that bureau "could have and should have done more to investigate the information it was provided prior to the shooting."

Get Breaking News Delivered to Your Inbox

"While we will never know if we could have prevented this tragedy, we clearly should have done more," he added.

Bowdich also highlighted the failures in the FBI's tip line, saying "some recommendations have been bridged" in an effort to revamp the tip process.

"As I wanted to be fully transparent on -- we made mistakes here. No question about that," FBI's Bowdich said the of the Florida shooting. "With that said, even if we had done everything right, I am not sure we could have stopped this act."

Meanwhile, ATF's Thomas Brandon advised lawmakers that he ordered a "review of policies and procedures" of tips into the agency and has already implemented a new system.

Officials also offered their opinion on proposed gun legislation after the Senate failed to pass any kind of gun reforms in the wake of the shooting and after President Trump signaled he would be willing to lend his support to such measures like enhanced background check systems.

Brandon said a notice of proposals on the issue of bump stock accessories, which Mr. Trump's Department of Justice has made moves on banning, is now in the hands of the Office of Management and Budget -- showing slow signs of progress. He noted, however, that such a ban could be challenged in the courts.

Bowdich meanwhile said he would describe legislation like "extreme risk protection orders" or gun violence restraining orders that would allow judges to temporarily strip gun rights from people who show warning signs of violence as a "sensible" action to consider.

Lawmakers at times appeared frustrated that even with glaring evidence that a problem existed it was not acted upon. They also highlighted Congress' inaction on providing common sense gun reforms in the wake of the tragedy.

"The 17 lives in Parkland, Florida are worth a lot more than the weak response we've heard from this committee and the president," said Sen. Dick Durbin, D-Illinois, as the chamber erupted into loud applause.

He added, "When 97 percent believe we should have universal background checks to keep guns out of the hands of people who misuse them and the students march, we ought to listen."

Durbin admitted that Mr. Trump had identified the reasoning behind the weak responses: "Politicians are petrified by the NRA and the question we face very honestly is whether or not we're petrified by them."

Here are some of the highlights from the hearing:

FBI provides details on tip process

When asked to explain how a tip on Cruz could have been missed by the FBI's tip line, Bowdich said, "We do not know what was presented" between the call taker and call supervisor. He suggested "in the future, one of the recommendations is there will be more fidelity on how that was presented and more of a thorough review on the supervisors part."

He later described the call-taking process as being "hard to listen to" and that many were deemed "nuisance calls" from repeat callers.

"They're challenging and those folks, they work hard out there, and they're making judgement decisions, in this case we've been 100 percent clear we do not believe the right decision was made," Bowdich added.

Asked if the FBI had taken any action to fire those involved in the missed tips, Bowdich replied, "these employees have due process like anyone else" and that as of today, no one has been terminated as a result of the misstep.

Bowdich later told lawmakers that while he's unsure if any sort of mental health law could have prevented the shooting, it "would've been nice to get in front of" Cruz and take along a state or local officers to intervene before the suspect carried out his plan.

Survivors, families call for common sense action

In an emotional portion of the hearing, a father of a Stoneman Douglas shooting victim and teacher from the the high school offered their own testimony on how lawmakers can best prevent further tragedies from happening again.

Ryan Petty, father of Alaina Petty who was fatally shot at Marjory Stoneman Douglas High, touted policy achievements made in the Florida state house in the wake of the shooting. "Americans are deeply interested in safe schools, caring communities and safe neighborhoods. We've learned at terrible costs that Americans can come together, we can agree on most fundamental things," Petty said.

He added of Florida's legislation, "They serve no political agenda, they serve the peoples agenda because they build on common ground. They're inclusive rather than divisive."

Petty stressed the need for nationwide improvements to security at schools as well as early identification and interdiction as a means to prevent mass shootings.

"If we can identify the potential violent actors and get the help they need, they don't have to resort to violence is the best way to prevent these."

Meanwhile, Katherine Posada, a teacher at Stoneman Douglas who was able to barricade students in her classroom until police arrived, described the survivors of being "stronger than teenagers ever have to be."

Posada denounced the president's suggestion of arming "capable" teachers as a means to prevent future shootings as "an idea that can only end in tragedy." She said the overwhelming cost of training teachers was also an issue, saying Broward County was more willing to spend money on arming teachers instead of allocating funds toward education.

She instead suggested increasing safety in schools, resources for those suffering from mental illnesses and banning weapons with high-capacity magazines.

"Until we take these guns away there really no way we can completely prevent these kinds of things from happening unfortunately," Posada added.