A heroic police dog named Diesel was killed in Paris Wednesday night after searching for alleged terrorist attack mastermind Abdelhamid Abaaoud in a city apartment. The seven year-old Belgian Shepherd, who was trained to sniff out explosives, was slaughtered by a female jihadist who attacked police with an AK-47 before detonating her suicide vest.

Diesel’s loss felt deeply the by Paris police department. “It’s a little like losing one our colleagues,” one of his handlers said.

Explosive-detecting dogs have become indispensable in Paris’ quest to fight terror and prevent more violence. The canine hero was the first to enter the apartment in order to assess the threat level inside. Almost immediately, a blonde woman allegedly married to Abaaoud emerged from a room wearing an explosive suicide vest and wielding an AK-47. She opened fire on Diesel and detonated her vest, killing herself and one other.

The explosion signaled the start of a standoff between other terrorists holed up in the apartment and police. The two groups exchanged gunfire for seven hours before Paris police was able to arrest at least six people.

Diesel was the only casualty connected to Parisian police, and his sacrifice has not gone unnoticed. The Twitter hashtag #JeSuisUnChien trended as people paid their respects to the fallen dog.

RIP Diesel.