A gold star mother from Rancho Cucamonga, California is honoring her Marine son's last wishes by taking in his beloved working dog, Sirius. She made that promise the very last time she spoke to him.

Sgt. Joshua Ashley was soon killed in Afghanistan by an improvised explosive device (IED). Sirius was with Joshua when he died. He was 23 years old.

Sirius sits on a memorial dedicated to Sgt. Joshua Ashley, his handler. (U.S. Marine Corps photo)

His mother, Tammie Ashley kept the promise four years later, after Sirius was retired from the Marine Corps. She picked the pup up at the airport in Ontario, California.

"It was the strangest thing," Ashley told CBS Los Angeles. "He was smelling my face like he was going to lick it, and it was almost like 'I recognize you.' Like, 'You were Josh's mom.'"

Sirius during his deployment to Afghanistan (U.S. Navy photo)

Sirius, a German Shepherd, was 7 years old when Ashley died. It was a big loss. The team of Ashley and Sirius scored a 100 percent in their pre-deployment training class. Four months later, on July 18, 2012, Ashley hit the IED that killed him.

Their story is recounted in author Rebecca Frankel's "War Dogs: Tales of Canine Heroism, History and Love."