BANGOR, Maine — The Penobscot County grand jury indicted a Millinocket man Wednesday in the death of a 6-month-old boy who died in May 2015 and was the son of accused murderer Anthony Lord.

Jessee Mackin, 33, was arrested Wednesday night and charged with manslaughter in connection with the death of Larry Lord Jr., the son of his girlfriend, according to Stephen McCausland, spokesman for the Maine Department of Public Safety.

“The baby died at the hospital after being brought there unresponsive by his mother in May, and State Police have been investigating the death since that time,” McCausland said.

The infant was taken to the hospital on May 5 and died on May 7, according to previously published reports.

The child’s death was mentioned in several Bangor Daily News stories about a deadly shooting spree involving his father that left two men dead.

Maine State Police and Maine Drug Enforcement Agency agents arrested Mackin in Millinocket and took him to Penobscot County Jail in Bangor.

He likely will make his first court appearance Thursday or Friday, McCausland said.

The child is survived by his parents and four sisters, according to his obituary.

Anthony Lord, who has a long criminal history and is a lifetime registrant of the Maine Sex Offender Registry, was arrested after a July shooting spree and manhunt that resulted in the deaths of Kyle Hewitt, 25, of Bangor and Kevin Tozier, 58, of Lee.

Lord is awaiting trial after entering a not guilty plea to the charges against him.