WASHINGTON — Top investigators looking into whether intelligence agencies missed key warning signs before the Boston Marathon bombings said Wednesday that there was no “silver bullet” that would have prevented the attack but there were several holes in the system.
Officials from the agencies said they are taking several actions to tighten intelligence-sharing and other procedures, as a series of congressional inquiries into the bombings winds down. The changes that are known publicly have not involved sweeping shifts in policy.
“There were some errors, there were some inaccuracies. And we’ve made some recommendations and drawn some conclusions,” Intelligence Community Inspector General Charles McCullough told a Senate panel reviewing the events leading up to the bombings. “But at the end of the day there’s not a smoking gun.’’
“There’s not a singular event or series of events that we can say, had this happened, that would have . . . stopped the bombing,” McCullough said.
The testimony from the four inspectors general followed the release of a report two weeks ago that detailed missed signals and an investigation into Marathon bombing suspect Tamerlan Tsarnaev that was only fleeting.
Wednesday’s congressional hearing was one of several examining whether official lapses allowed home-grown terrorists to escape detection.
The investigators concluded that Tsarnaev, as well as his mother, should have received more scrutiny after Russian intelligence agencies warned them in 2011, before his travel to Russia. Instead, Tsarnaev only got a cursory look and the FBI cleared him as a potential threat without searching all available databases or conducting interviews with his friends, his wife, or his ex-girlfriend.
“It’s a cascade of very small judgments that were made that, had they been made differently, it wouldn’t have happened,” Senator Tom Coburn, an Oklahoma Republican and the ranking member on the committee, said in an interview after the hearing.
“That’s Monday morning quarterbacking — and probably I would have made the same assessment sitting in their position,’’ Coburn said. “But it should highlight for us what we should be doing and what we should be changing. Because the information was there. It just wasn’t put together.”
When asked whether he had a sense of what changes might occur as a result he said, “Yeah, but most of it I can’t talk about because most of it’s classified.”
Members of Congress have been trying to determine whether enough has been done to prevent a similar attack in the future. Little legislation is expected to be filed, however, with much of their efforts focused instead on trying to persuade US agencies to change their procedures.
Several changes have been made, according to those who testified at the hearing. All persons of interest leaving the country are given a deeper look by customs agents; information put into terrorist watchlists has been enhanced; and FBI and CIA agents have been reminded to share more information.
In one indication that Washington’s appetite for examining the Marathon bombings has faded, only one Democrat and three Republican senators attended the hearing before the Senate Committee on Homeland Security and Governmental Affairs, which was held in a room that was half full and included only two reporters.
There have been several reviews of the Boston Marathon bombings by federal agencies and members of Congress, but the group of inspectors general produced one of the most comprehensive.
There were two reports produced by the inspectors general. One was made public and the other, much longer version, was classified.
The public report contained several areas that were redacted. The four inspectors general who produced the report wanted those sections to be made public and saw no reason for them to be classified. But the agencies involved overruled them.
“There was some pretty vigorous disagreements about that,” McCullough said after the hearing. “We wanted the entire thing unclassified. We feel like everything in there is unclassified. The agencies disagree with us on it.”
“We’re still battling those things,” he added. “We’re trying to get the whole thing unclassified.”
There were also hints that more should have been done to examine Tsarnaev’s mother, Zubeidat Tsarnaeva. The initial tip from the Russian intelligence agencies warned about both Tamerlan Tsarnaev and his mother — saying they were “adherents of radical Islam” — but the FBI opened up an assessment only into Tamerlan.
The warning also said Tamerlan Tsarnaev was preparing to travel to Russia to join unspecified “bandit underground groups.” The agent doing the assessment into Tsarnaev did not ask about any possible travel to Russia.
At Wednesday’s hearing, Coburn initially began a line of questioning about Tsarnaev’s mother — and whether there is a system in place to review people who return to a country they had initially sought asylum from — but he stopped and said he would have to continue the line of questioning in a classified setting.
“There was information that we found,” McCullough said. “We examined the post-bombing information that was collected and I think probably that would have to be discussed in the classified session.”
“I too have information and I’ll report in closed session,” said David B. Buckley, the inspector general for the CIA.
Even without the Russian tip, McCullough said, intelligence agencies could have discovered Tsarnaev’s radicalization — an important distinction for those who worry about how US intelligence agencies can prevent similar attacks if they are orchestrated outside more traditional terrorist networks.
“In a classified session we can talk about some of the post-bombing forensics and what was found and that sort of thing, and you can see when that radicalization was happening,” McCullough said.
“I would think that this would have come up, yes . . . to law enforcement and to the intelligence community. Possibly not as early as [the warning from the Russians]. But it would have come up at some point knowing what we found post-bombing,” he said.
As several senators emerged from the classified portion of the briefing, they said they felt comfortable with some of the actions being taken.
“I think we’d make a mistake to say that everything that should be done has been done,” said Senator Tom Carper, a Democrat from Delaware and the chairman of the committee. “Because the folks who wish us ill are always going to be looking for new ways to hurt us, and hurt our people.’’