A man suspected in a series of stabbing and hit-and-run attacks that killed three people and injured three others in two San Francisco Bay Area cities has several felony and misdemeanor convictions, authorities said Friday.Kevin Parkourana, of San Jose, is suspected in the attacks that began Thursday afternoon in a San Jose shopping center parking lot and ended at another shopping center in the neighboring community of Milpitas, where police arrested him.The attacks appeared to be random, San Jose Police Chief Anthony Mata said. He said Parkourana has several felony and misdemeanor convictions spanning several years and that it's not yet clear why he was released given his criminal history."We have to look at each individual crime that he was convicted of to figure out what happened, and that's something that we're working with the district attorney's office to figure out," he said.Parkourana stabbed two people during two carjackings in separate parking lots, leaving both people with life-threatening injuries, San Jose police officials said.He then allegedly struck a pedestrian with a car in one of the parking lots, intentionally hit two people standing outside a home and later struck someone riding a scooter, San Jose Deputy Police Chief Steve Logorio said.The couple outside the home died.About an hour-and-a-half after the first stabbing took place, Parkourana allegedly committed another stabbing at a shopping center parking lot in neighboring Milpitas. That victim died at a hospital, Milpitas Police Chief Jared Hernandez said.A motive in the attacks has not been determined, Hernandez said."Detectives from the Milpitas Police Department and the San Jose Police Department continue to work collaboratively as we try to piece together the events that happened yesterday and identify a motive behind the person's actions," he said.