– A Frenchman who had escaped at least two earlier U.S.-led attempts on his life for defecting to Al-Qaida died in a July airstrike, the Pentagon said Tuesday.

David Drugeon, who had converted to Islam in his teens after becoming radicalized in French and Egyptian mosques, was killed July 5 in a strike near Aleppo, Syria’s second-largest city and the site of fierce fighting in its four-year civil war.

“He was specifically targeted,” said Pentagon spokesman Navy Capt. Jeff Davis.

Analysts said Drugeon’s death was significant because he had become a master bomb maker who specialized in assembling plastic explosives and because he symbolized the hundreds of Europeans who have become radical Muslims and joined Al-Qaida and the Islamic State in Iraq and the Levant (ISIL).

Pentagon press secretary Peter Cook said that Drugeon, 25, was a member of the Khorasan Group, a small cell of experienced Al-Qaida militants who have coordinated with Nusra Front, Syria’s main Al-Qaida affiliate.

“As an explosives expert, he trained other extremists in Syria and sought to plan external attacks against Western targets,” Cook said. “This action will degrade and disrupt ongoing external operations of Al-Qaida.”

In a more recent airstrike in Iraq, on Sept. 10, U.S.-led forces killed Abu Bakr al Turkmani, described by the Pentagon as an “administrative emir” of ISIL and “a close associate to multiple ISIL senior leaders.”

But it was the reported death of Drugeon that drew the attention of terrorism analysts because he was a Frenchman who defected to Al-Qaida after receiving military and intelligence training from France in the apparent hope of planting him inside the radical group and using him as an informant.

Instead, when Drugeon arrived three years ago in Waziristan, a region of Pakistan that has long harbored radical Islamists, he reportedly told Al-Qaida leaders that he was a French spy and wanted to join their ranks.

Drugeon subsequently received training in assembling explosives and became an expert bomb maker.

French officials tried to downplay Drugeon’s defection, but his importance was underscored on Sept. 23, 2014, when the U.S. launched its first strikes in Syria, targeting him and other Khorasan operatives. Drugeon survived that strike and another in November 2014.