Byron, ME – Four young people celebrating a birthday and a graduation at a cabin in Maine likely died of carbon monoxide poisoning hours after their arrival earlier this week, a sheriff said Saturday.

The Oxford County Sheriff’s Department said it is believed that the victims were overcome by carbon monoxide on Tuesday, but their deaths are still under investigation.

“It appears that they may have unintentionally ran a generator that was still in the confines of the building,” Sheriff Wayne Gallant told WBZ NewsRadio 1030. “We believe it was carbon monoxide that took them all over.”

The generator was being used to run electricity to a refrigerator, Gallant said.

“More than likely it happened the first night there,” he said.

The victims were identified Saturday as 22-year-old Deanna Powers, of Mansfield; 23-year-old Keith Norris, of Attleboro; 18-year-old Matthew Wakelin, of Mansfield; and 21-year-old Brooke Wakelin, of Attleboro.

“It’s a shocking and terrible reminder to people that carbon monoxide is dangerous,” he said. “You never have a generator in the house.”

Gallant said the victims drove to the camp Tuesday to celebrate Matthew Wakelin’s graduation and Brooke Wakelin’s 22nd birthday, which would have been Saturday.

A medical examiner was running tests to confirm the cause of death, Gallant said.

Two of the victims were found in a downstairs bedroom, Gallant said. The other two were found in separate bedrooms upstairs.