Motive Sought for Dad Suspected of Being I-96 Shooter

Raulie Wayne Casteel is shown in a booking photo, Nov. 7, 2012, in Howell, Mich. (Livingston County Sheriff/AP Photo)

Michigan police believe they have caught the I-96 shooter, but are now trying to find a motive for why the geologist and father of a young girl allegedly went on a shooting spree.

Raulie Casteel, who was arrested earlier this week, is believed to have fired on two dozen cars in the Detroit area over the past month.

On Monday Casteel, 43, was arrested in connection with a shooting that took place on the Interstate 96 outside of Detroit on Oct. 18. According to prosecutors he is expected to face more charges in the other jurisdictions over the 24 shootings that terrorized a four county area of Michigan since mid-October.

"We had so many people who were so afraid to travel down 96, parents pulling their kids out of school. So, for us it was a very big challenge to go out here and find this guy," Lt. Mike Shaw of the Michigan State Police said.

Livingston County Sheriff/AP Photo

Raulie Wayne Casteel is shown in a booking... View Full Size

Livingston County Sheriff/AP Photo

Raulie Wayne Casteel is shown in a booking photo, Nov. 7, 2012, in Howell, Mich.

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Casteel was arrested after a raid on his home in Wixom, Mich. During the raid police seized two handguns which they believe Casteel used to pump bullet holes in two dozen vehicles during the terror spree.

Police told ABCNews.com that re-interviewing their witnesses ultimately led to their big break. One of the drivers, who was uninjured, gave a description of the shooter's car, and was able to identify part of the license plate. The driver also noticed a logo for Michigan State University – Casteel's alma matter-- on the car.

"We did some follow up on interviews with some old witnesses that kind of pointed us in the right direction," Shaw said. "We used some good old fashion police work to go ahead and find a lead for us to get this guy."

Authorities said that Casteel had a license to carry a pistol in Kentucky, but not in Michigan.

Casteel is being held on $2 million bail after being charged. It is unclear if he entered a plea. He is charged with six counts for the shooting in Livingston County, including three counts of felony firearms, one count of assault with a dangerous weapon, one count of assault with a dangerous weapon with unlawful intent, and one count of discharging from a vehicle.

Only one person was hit during the string of shootings across a 100-mile stretch of roads in Oakland, Livingston, Ingham and Shiawassee counties. That victim was seen on surveillance footage limping into a gas station with a bullet wound to the buttocks, looking for help.