PORTLAND, Maine – A 74-year-old Maine man was charged in the shooting deaths of two tenants inside an apartment he rented out at his home, and detectives are investigating whether the violence is connected to a landlord-tenant dispute, state police said Sunday.

James Pak was arrested at about 10 p.m. Saturday following a standoff at his suburban neighborhood home in Biddeford, about 15 miles south of Portland, police said. He is charged with two counts of murder in the deaths of Derrick Thompson, 19, and Thompson's girlfriend, 18-year-old Alivia Welch.

Thompson's mother, Susan Johnson, 44, had called police to Pak's home about three hours earlier. She and her 6-year-old son also live in the apartment, which is attached to the main house where Pak lived.

Biddeford police rescued Johnson and her young son, and Pak retreated to his part of the house. He surrendered hours later after talking to police negotiators, said state police spokesman Steve McCausland. A gun was found in the house.

Johnson was being treated for a gunshot wound at a Portland hospital, officials said. Her younger son, Brayden, was not hurt.

Detectives are investigating whether the violence stemmed from a landlord-tenant dispute, McCausland said. Johnson and her family moved into the apartment in October.

Pak is being held at the York County Jail in Alfred and is expected to make his initial court appearance either Monday or Wednesday, depending on the availability of a judge.

The victim's bodies were transported Sunday to the medical examiner's office in Augusta, where autopsies will be performed.

Thompson was an auto detailer at a local car dealership and had attended Biddeford High School, and Welch worked at a local coffee shop and graduated from Thornton Academy in Saco, according to their Facebook profiles and a list of Thornton Academy graduates. Two people who answered a phone call at the coffee shop would not comment.

Welch and Thompson married in July, according to both their Facebook profiles, but McCausland said police weren't aware whether they were married.