Former NFL player, Doug Martin, 36, died after what police described as a “brief struggle” with officers who arrested him early Saturday while investigating a break-in at a home. He became unresponsive and was pronounced dead at a hospital, Oakland police said. A cause of death has not been released.

Many questions are unanswered, including how many officers were involved, how long they struggled with Martin and how they restrained him. The officers who detained him have been placed on paid leave while the investigation continues, a standard police practice.

Martin's former agent issued a statement Monday at the request of his family saying that Martin privately battled mental health challenges that “profoundly impacted his personal and professional life.”

On the day he died, Martin felt overwhelmed and disoriented, fled his home and entered a neighbor’s home two doors down, where police confronted him, said the former agent, Brian Murphy.

Martin’s parents had sought medical help for him and contacted local authorities for support, Murphy said. “Ultimately, mental illness proved to be the one opponent from which Doug could not run,” he said.

Doug Martin arrived on the campus of Boise State University nearly two decades ago to play football on its famed blue turf and, despite being a squat, little-known recruit from Northern California, turned himself into a hard-nosed running back and a first-round NFL draft pick.

Nicknamed the “Muscle Hamster” for both his size and running style, he was twice named to the Pro Bowl with the Tampa Bay Buccaneers during a seven-year NFL career. But his bruising ways on the field also caused him to miss extensive playing time with a variety of injuries and contributed to his retirement.