AUBURN — A Minot man who police say shot up his home and later burned it down, then set fire to his estranged wife’s home and ran her off the road pleaded not criminally responsible, claiming he was insane at the time of the events.

Michael Callahan, 45, of 185 Verrill Road, Minot faces several felony charges, including attempted murder and three counts of arson stemming from a May 24 rampage in Minot and Mechanic Falls, according to court records.

The previous December, Callahan held police at bay at his home after he reportedly threatened his wife and children over an argument between him and and his then-16-year-old daughter. Callahan had been investigated by the state and accused of abusing his then-12-year-old son. His daughter called 911, then his wife and kids fled the home, according to court records.

The standoff started about 10:30 p.m. on Dec. 21, 2012, when police were called to the Callahan home. An overnight standoff ended peacefully with Callahan surrendering to police about six-and-a-half hours later, after a tactical team member returned fire.

Callahan fired about a dozen rounds, police said, and an assault weapon was among the guns seized. He had fired a rifle and machine gun at police, according to court records.

No one was injured during the standoff.

Police later discovered an arsenal of 22 handguns, 26 rifles and six shotguns at the home.

He was later charged with several counts of reckless conduct, domestic violence criminal threatening and aggravated criminal mischief.

Callahan was scheduled to undergo a court-ordered mental examination earlier this month to gauge his competency to stand trial, as well as his sanity at the time of the events, when police say he committed the crimes with which he is charged. The examination also was expected to determine whether he suffered from abnormal condition of the mind at the time of those events relating to the charges.

Callahan entered pleas of not criminally responsible by reason of insanity, a so-called “affirmative defense.” That means his attorney, James Howaniec, must prove to a jury by a preponderance of evidence that Callahan didn’t have the capacity to appreciate the wrongfulness of his actions at the time of the events because of a mental disease or defect.

Prosecutors will have the burden of proving beyond a reasonable doubt that Callahan was guilty of committing the crimes. If he were found guilty but insane at the time of the events, he would be committed to Riverview Psychiatric Center in Augusta under the auspices of the Department of Health and Human Services.

Howaniec also is expecting to claim during Callahan’s trials that he suffered from an abnormal condition of mind, a factor that could help raise reasonable doubt as to his culpability.

Howaniec said Callahan was taking more than a dozen prescribed medications for his deteriorating physical health due to multiple sclerosis, coupled with depression, anxiety and paranoia about his failing marriage.

Howaniec said Thursday that Callahan has retained the services of a prominent Maine psychologist, who examined the defendant and is expected to testify at trial about Callahan’s state of mind at the time of the events related to the charges.

A June trial is expected on the charges related to the police standoff.

Police said that on May 24, Callahan had driven to Mechanic Falls, where his estranged wife worked at a local school. As she drove away in her minivan, he rammed that vehicle from behind with his pickup truck, spinning the van around. He then circled around and rammed the side of the van two more times, according to court records.

He exited his truck and walked in her direction. She fled the scene on foot and later was transported to a hospital.

He also was charged with trying to ram the cruiser of an Androscoggin County Sheriff’s deputy in Minot and was later stopped by police in Hebron.

Police said Callahan had set fire to his home at 185 Verrill Road in Minot earlier that day before driving to Mechanic Falls and setting fire to the mobile home in which his estranged wife had been living.

cwilliams@sunjournal.com