PHILADELPHIA — John “Jack” Agnew, one of the original members of an Army unit that operated behind enemy lines in World War II and is often credited with having loosely inspired the movie “The Dirty Dozen,” has died at age 88.

Agnew belonged to the Filthy Thirteen, an unofficial unit within the 506th Parachute Infantry Regiment, 101st Airborne Division. He was pronounced dead Thursday at Abington Memorial Hospital after becoming ill at his home in the Maple Village retirement community in Hatboro, where he and his wife moved about a year ago, his daughter Barbara Agnew Maloney said.

On D-Day, the Filthy Thirteen parachuted into France to take a bridge over the Douve River. It was “a mission that would cost most of the men their lives,” according to an article in the winter 2008-09 edition of American Valour Quarterly, a publication of the nonprofit American Veterans Center.

Before the Battle of the Bulge, Agnew and others in the unit were requested for pathfinder duty and parachuted into Bastogne, which was besieged by German forces. Agnew operated a beacon to help guide in planes carrying badly needed supplies.

Tales of the unit’s exploits and a Stars and Stripes military newspaper photo are said to have inspired “The Dirty Dozen,” not because the unit’s members were convicts like the movie’s characters – they weren’t – but because of their reputation for brawling, drinking and spending time in the stockade.

In interviews, Agnew said that came directly from the unit’s leader, Jake McNiece.

“We weren’t murderers or anything, we just didn’t do everything we were supposed to do in some ways and did a whole lot more than they wanted us to do in other ways,” he told the quarterly.

Agnew was among those interviewed in a documentary, “The Filthy Thirteen: Real Stories from Behind the Lines.”