SACO, Maine — Neighbors struggled to make sense of the shooting deaths of a family of five in which the father was known to many throughout their apartment complex as a friendly maintenance worker.

Three children ranging from 4 to 12 were among the victims discovered Sunday in their home along with a long-barreled gun believed to have been used in their deaths. A detective said murder-suicide was one of the scenarios being investigated.

“I still don’t want to believe it,” said Heather Nason, who used to babysit the three children. “I love those children like they were my own.”

Investigators said it appeared no one outside the family was responsible for the shootings. They planned to release the identities today.

The grisly discovery was made after a family friend contacted an apartment complex worker to express concerns about the family’s well-being, investigators said. The worker entered the apartment and discovered one body, then immediately called police.