Walter E. Ellis, 49, has been charged in the deaths of two of the nine victims, and more charges are expected this week, prosecutors said Monday.
He was captured by police after an alert officer spotted his car at a motel, authorities said.
Ellis had been in trouble with the law before. He pleaded no contest in 1998 to a reduced charge of second-degree reckless injury and served three years of a five-year sentence, police Chief Edward Flynn said. That wasn't enough to raise red flags, he added, without providing additional details about that crime.
"Yes, he does have a criminal history," Flynn said. "His criminal history, however, does not lend one to immediately say, you know, 'prime suspect.'"