In the early hours on Wednesday, French law enforcement officials conducted a raid on an apartment building in a suburb north of Paris, St-Denis, where Abdel-Hamid Abu Oud—the alleged mastermind behind last Friday’s Paris attacks—was believed to be hiding.

After seven hours of heavy gunfire and series of explosions, two suspects were killed and seven were arrested. The officers also suffered one casualty: a police dog named Diesel. The seven-year-old Belgian Shepherd was sent into the apartment building first and was killed when a woman inside detonated an explosive device she was wearing.

The National Police announced on Twitter that Diesel “was killed by terrorists in the current operation” and posted a photo of her emphasizing how important she was to the mission.

Les chiens d'assaut et de recherche d'explosifs: indispensables dans les missions des opérateurs du #RAID pic.twitter.com/vb5lGjnwjO — Police Nationale (@PoliceNationale) November 18, 2015

Not long after the hashtags #Jesuisunchien (“I am dog” in English) and #NotAllHeroesAreHuman spread across Twitter as people around the world honored and mourned Diesel.

#JeSuisUnChien that dog was a Hero and gave his life for us humans 🐶❤️🐒 pic.twitter.com/2PMbRCerhw — Colja Nowak (@ColjaNowak) November 18, 2015

On Reddit, users shared stories and quotes commemorating Diesel and and other service dogs who have died in the line of duty.

Others commented on the close connection service dogs share with their handlers.