WIXOM — A Michigan man was sentenced to 12 years in prison on Tuesday for a three-day shooting spree in October 2012 on a busy interstate highway that earned him the nickname “I-96 shooter,” court officials said.

Raulie Casteel, 44, who was convicted last week in a separate case involving the highway shootings, was sentenced Tuesday in Oakland County Circuit Court on his plea of no contest but mentally ill to assault and firearm charges.

His attorney, Douglas Mullkoff, said Casteel, who had testified that he opened fire on motorists because he believed they were part of a government conspiracy against him, suffered from a “delusional disorder.”

Casteel faces up to life in prison when he is sentenced in March on his conviction last week on terrorism charges by a jury in Livingston County. In both cases, he was accused of shooting at other vehicles in a four-county area in southeastern Michigan, mostly on or near Interstate 96.

During Tuesday’s hearing, Oakland County Circuit Court Judge Denise Langford Morris thanked God that Casteel was a “lousy shot,” because no one was injured in the spree, the Detroit Free Press reported.

One person was initially reported to have been wounded, but further investigation revealed that the bullet had not come from Casteel’s gun, Mullkoff said.

Asked about the judge’s comment, Mullkoff said Casteel was actually a “good shot,” and he had not been shooting at people, but at cars, which is why the Livingston County jury had found him not guilty of assault with intent to murder.

Casteel, who lives in Wixom, Michigan, a community about 30 miles northwest of Detroit, is scheduled to be sentenced on March 3 in the Livingston County case.