LAPD Officer and Marine Staff Sgt. Joshua J. Cullins

Los Angeles police Wednesday were mourning a 28-year-old Marine Corps bomb specialist killed in a roadside blast in Afghanistan's Helmand province.

Staff Sgt. Joshua J. Cullins died Monday. He became the second LAPD officer killed this year with Marines in the war-torn province.

"Joshua was a highly respected Marine staff sergeant and LAPD officer who was honorably serving our country as a Marine reservist in Afghanistan when he was killed," Los Angeles Police Protective League President Paul Weber said Wednesday.

"This is a great loss for the LAPD and for everyone who knew him and witnesses his commitment to upholding his duty and honor as a police officer and a Marine. Our deepest condolences go out to his parents, family and friends."

Cullins, an explosive ordinance disposal officer, had recently recovered from a concussion he suffered July 16 while dismantling another roadside bomb.

Buoyed by his friends' messages and by the accompanying music video dedicated to him, Cullins bounced back quickly. But on Tuesday, his friends learned that he had Cullins died trying to disarm another bomb.

Police sources told the Los Angeles Times that Cullins was killed by a secondary bomb as his unit was investigating an earlier explosion.

A Marine Corps reservist, Cullins was serving with the 3rd Battalion, 6th Marine Regiment in Marja, in Afghanistan's dangerous Helmand province.

A two-part "Welcome Home" video for Cullins includes personal messages from Chief Charlie Beck to rookie patrolmen, telling "Josh" they were looking forward to seeing him back at work in Los Angeles.

"There are no words to express how we feel," Capt. Daryl Russell said Tuesday. Russell commands patrol officers at the downtown Central Station and he was Cullins' LAPD boss.

"I'm so sad this has happened to a kid who really had a bright future with this police department," Russell said. "This is a total loss to this city and this country."

Cullins was being courted by the LAPD's bomb squad because of his expertise dismantling bombs with the Marine Corps Reserve, Russell said.

After his concussion, Cullins returned to the field as quickly as doctors would allow, Russell said.

"He'd put in his time and could have had a desk job," Russell told The Times. "He continued wanting to be out with his fellow Marines, doing the job every day he strapped on his boots."

Russell commissioned the "Welcome Home" video. Officer David Marroquin, who has video production experience, recruited a friend, actor- musician J. Hunter Ackerman, to write and perform music for what became a nearly five-minute video.

The video was shot at the Salton Sea, the Farmers Market on Third Street, local police stations and from the top of the 52-story Gas Co. tower downtown.

Cullins is survived by his parents, Jim and Barbara Cullins; and brothers, Cooper, 12, and Donovan, 16.