The Portland Press Herald is reporting M.D. Harmon, a well-known conservative newspaper columnist, has died after a gun was improperly fired in his home by a visiting teenager. Harmon was showing one of his guns to the young man:

Police say the 71-year-old Harmon died at his home on Brunell Avenue after a handgun he was showing a teenage boy went off. The 16-year-old boy was handling the gun at the time.

Harmon, a steadfast defender of gun rights and champion of conservative viewpoints, was a longtime Maine Sunday Telegram and Press Herald editor and columnist. He worked for the newspapers for 41 years before retiring in 2011, although he continued writing a weekly column.

The teenage boy and his father, both from North Berwick, were visiting Harmon’s home at the time of the shooting, police said. Detectives said they have been cooperating with the investigation and will be undergoing more questioning on Thursday.