RODEO, Calif. -- Investigators are following promising leads Wednesday afternoon in their search for a suspect who attempted to carjack a man in Rodeo Tuesday, causing the man to strike a pedestrian and drag him to his death, Contra Costa County sheriff's Capt. Daniel Terry said.

Shortly after 4 p.m., 28-year-old David Delgado, a San Pablo resident, was in the 1000 block of Mariposa Street in Rodeo when 69-year-old James Gilbeaux asked him for a ride.

The two men knew each other and Gilbeaux was walking around Delgado's truck, a Ford F-150, to get in when an armed man approached the vehicle and attempted to carjack it, Terry said.

Delgado reportedly resisted and the gunman fired four to five shots.

Delgado stepped on the gas and was attempting to flee when he accidentally struck Gilbeaux and dragged him for 100 to 150 feet, Terry said.

The gunman fled on foot from the area before deputies arrived, Terry said.

Gilbeaux was taken to Doctors Medical Center in San Pablo, where he died from his injuries, Terry said.

Delgado remained at the scene and cooperated with investigators. Witnesses corroborated Delgado's story, Terry said.

If investigators catch him, the gunman could be charged with attempted carjacking, assault with a deadly weapon, and, under the state's felony murder rule, he could also be charged with murder for causing Gilbeaux's death, Terry said.