A man who died while being taken into custody on state Highway 4 in Pittsburg this morning has been identified as 38-year-old Rio Vista resident Edward Nash, a Contra Costa County deputy coroner said.California Highway Patrol officers responded to westbound Highway 4 at about 3:30 a.m. after receiving reports of a pedestrian running through lanes on both sides of the highway east of Harbor Street, CHP Officer Tom Maguire said. Before officers arrived, private security guards traveling through the area saw Nash crossing the highway and stopped to try to get him off the road.Nash reportedly started to fight the guards as they attempted to restrain him with handcuffs, Maguire said.When CHP officers arrived, Nash was allegedly continuing to fight,even after they put him in leg restraints to subdue him so that they could remove him from the roadway.During the struggle, Nash’s body went limp and he stopped breathing, Maguire said. CPR was initiated, and paramedics from the Contra Costa County Fire Protection District were called. Efforts to resuscitate him were not successful, Maguire said, and he was pronounced dead.A westbound lane of the highway was closed for several hours while authorities investigated the incident. A Sig-alert issued shortly before 6 a.m. was canceled at about 8:45 a.m., CHP Officer Nicole Pacheco said.An autopsy was conducted on Nash today, but his cause of death is still pending, according to the coroner’s office.Because Nash died in custody, the sheriff’s office will hold an inquest into his death. During the inquest, a jury will hear accounts of what happened and be asked to determine whether Nash died of natural causes, by accident, by suicide or whether his death was a homicide.