A 29-year-old Virginia man died over the weekend after Prince William County police tried to subdue him with a Taser, authorities said.

They said an investigation is underway into the death of Debro Lamonte Wilkerson of Manassas, who was involved in a confrontation Saturday with police and rescue personnel in the area of Hiram Court, where a relative lived.

After rescue personnel responded to a medical emergency, they called for police to help them with a combative patient. When police arrived, they were informed that Wilkerson had assaulted several firefighters.

Police said Sunday that in an ambulance, Wilkerson took an aggressive position and screamed at a paramedic. An officer intervened and warned Wilkerson to cooperate, police said, but Wilkerson lunged at the officer, who used the Taser in self-defense.

After Wilkerson jumped from the ambulance, yelled at police and assaulted a relative, he was brought back to the ambulance. Police said in a statement that Wilkerson told officers he had used heroin and PCP.

Despite repeated efforts to calm him, Wilkerson again lunged at an officer, knocked him down and fled, police said.

Officers followed him and again used the Taser. Wilkerson fell but continued to struggle while being treated by paramedics, police said.

He became passive and was carried on a stretcher to the ambulance, but his vital signs deteriorated, and he appeared to be without a pulse. Paramedics tried to resuscitate Wilkerson, but he was pronounced dead at a hospital, police said.

Some police departments have adopted Tasers, which are electroshock devices, as a nonlethal alternative to firearms. But several deaths in the Washington region have been associated with Taser use. Two were reported last year in Arlington.

A sister-in-law, Tammie Fitts, said she had called 911 on Saturday after Wilkerson, who had just showered, said he believed he was having a heart attack. His pulse was racing, she said.

After paramedics arrived and began treating Wilkerson, who was in socks and underwear, he became delusional and combative, Fitts said. She said he was Tasered three times, and “after the last time, he hit the sidewalk and never got back up.”