According to Belgian intelligence officials, a spy operation conducted by the National Security Agency at a funeral of a suicide bomber led to the capture of a fugitive from last year’s Paris attacks.

BuzzFeed News reported over the weekend that the arrest of Salah Abdeslam, the lone terrorist survivor of the Paris assault that killed 130 people last year, was facilitated by signals intelligence collected by the US spy agency on funeral-goers.

Abdeslam was nabbed by authorities in March, days after the NSA gathered cellular phone data in bulk on individuals who attended the burial of Chakib Akrouh, who died after he detonated a suicide bomb vest during a confrontation with police days after the Paris attacks.

“We called the American [National Security Agency] before the funeral,” one Belgian security official told BuzzFeed. He added that the spies “grabbed all the information about all the phones present [at the funeral].”

Although agents reportedly scanned the phones of all attendees at the funeral, Belgian security service sources stated that they had their eye on one known associate of Abdelslam who was on hand videotaping the proceedings.

“The guy is filming on a smartphone — that tells us he’s going to send that file to someone, right?” the individual said. “We had the NSA hit that phone very hard.”

A Belgian analyst told the outlet that although his nation’s security forces are capable of wiretapping and phone surveillance, the NSA can collect and analyze bulk data much more efficiently.

“As Edward Snowden has so helpfully explained to everyone, the NSA are the best at signal intercepts,” they stated.

The NSA did not respond directly to Buzzfeed’s request for comment, but did send along an article in which the Director of National Intelligence, James Clapper claimed that the agency is “always striving toward more integrated intelligence” with NATO allies.

As the Belgian security alluded to, the extent to which the NSA conducts bulk surveillance on foreign populations—both with and without the consent of the home government—was revealed in 2013, via documents leaked to journalists by whistleblower Edward Snowden.

President Obama announced new reforms to the agency in 2014 to rein in some of its activities, including affording privacy protections to foreign citizens whose information had been swept up into the NSA’s vast databases.