Police: Gunman kills 3, himself in southern California shooting spree February 19, 2013 -- Updated 2140 GMT (0540 HKT) A man, believed to be the shooter, lies dead in the street near an Orange County Sheriff's vehicle in Villa Park, California. Police: Gunman shot at several vehicles on Orange County freeway Authorities: Man killed two people, wounded two others during three carjackings Man also suspected of killing woman at home in Ladera Ranch, California, police say Suspect killed himself after police spotted him north of Tustin, police say (CNN) -- A man went on a carjacking and shooting spree on and near a freeway in Southern California's Orange County on Tuesday morning, killing three people and injuring at least three others before fatally shooting himself, police said. The suspect, identified only as a man in his 20s, executed at least one of his victims during one of the carjackings and fired at a number of vehicles in the Tustin area near the Costa Mesa Freeway and I-5, authorities said. "Several gunshots ... were fired on the freeway while the suspect was driving on the freeway or he had stopped and gotten out of his vehicle and fired rounds at passing motorists," Tustin police Lt. Paul Garaven said. Police said the rampage, as far as investigators know so far, began with the fatal shooting of a woman at a home in Ladera Ranch in southern Orange County. The county sheriff's department says it was called to the home on a report of shots fired about 4:45 a.m. About 25 minutes later and 22 miles to the northwest, the suspect is believed to have carjacked someone -- and shot him -- in Tustin near I-5. The victim was being treated Tuesday morning. Police said they believe the same carjacker, about 1 mile away, then ordered another person out of a BMW on the Costa Mesa Freeway. The gunman "orders him out of the vehicle, walks him to the side of the curb and executes our victim," Santa Ana police Cpl. Anthony Bertagna said. Later, police said, the gunman is believed to have carjacked and shot two people, killing one, outside a Micro Center computer store in the Tustin area. Between carjackings, the gunman shot and struck at least three vehicles, injuring at least one other person, police said. Eventually, after police spotted the suspect, he exited his vehicle and shot himself at an intersection about 5 miles north of Tustin, police said. "We are still investigating how many more victims we might have," Garaven said. CNN's John Fricke contributed to this report. February 19, 2013 -- Updated 2037 GMT (0437 HKT)