A former Portland Press Herald columnist was shot and killed Wednesday evening as he was showing a handgun a 16-year-old boy, police said.

M.D. Harmon, 71, of Sanford was a longtime Maine Sunday Telegram and Press Herald editor and columnist. The Press Herald says he worked for the newspapers for 41 years. He continued to write a weekly column after retiring in 2011.

The shooting occurred at Harmon's home on Brunell Avenue, Stephen McCausland, spokesman for the Maine Department of Public Safety, said in a news release Thursday.

McCausland said the teenager was handling the gun when it went off. The boy's father was also at Harmon's home at the time of the shooting.

The boy and his father, both from North Berwick, have been cooperating with the investigation, the release said.

An autopsy will be performed at the State Medical Examiner's office in Augusta, and the case will be reviewed by the Attorney General's Office.