A 17-year-old Florida boy bludgeoned his parents to death with a hammer and then invited dozens of friends via Facebook to a house party while the bodies lay in a bedroom, police say.

Tyler Hadley, a high school dropout from Port St. Lucie, Fla., was arrested on two counts of first-degree murder in the killings of Blake and Mary Jo Hadley.

Get push notifications with news, features and more.

Acting on an anonymous tip, officers visited the home Sunday morning and Tyler initially told them his parents were out of town, says Capt. Don Kryak.

Police entered the house and found the bodies in the locked master bedroom on the floor. The bodies were partially covered with towels, books and files, and a hammer believed to be the murder weapon lay between them.

“It was a merciless killing,” says Kryak.

Hadley then hosted a party in the house attended by as many as 60 people invited over Facebook. The party went from about 9 p.m. until the early hours of Sunday, police say.

“He had the party after the homicides took place,” says Kryak. The invitation had gone out before the murders, he adds.