A female American Airlines flight attendant has been found dead with a sock in her mouth in a hotel room near Philadelphia’s Airport, according to ABC News’ Philadelphia station WPVI. She was supposed to have checked out two days earlier.

Cleaning staffers discovered the unnamed 66-year-old victim late Monday evening at approximately 10:45 p.m. at the Philadelphia Airport Marriott directly adjacent to Philadelphia International Airport.

It is unclear why her body went undiscovered during that period, but authorities were immediately notified after cleaning staff made the discovery.

“It’s very strange,” Tracee Quinn of Ferris Hills, Pennsylvania, told WPVI in an interview. “And it seems like [there are] a lot of unanswered questions. But it is very sad.”

“Everybody is still trying to figure out what happened and why her crew just left her,” a source who works as a flight attendant for American Airlines told PEOPLE, noting they learned the woman’s crew was Los Angeles-based.

Several sealed bottles of prescription drugs were found in the room, according to WPVI, but police also reported that there were no signs of forced entry, struggle or any weapons recovered during their investigation.

Police said the case is suspicious and that the Homicide Detectives Division is now investigating.