Published: Jul 18, 2011 11:08 PM EDT
Updated: Jul 18, 2011 8:05 PM EDT

PORT SAINT LUCIE, Fla.- Tyler Hadley is charged with two counts of first degree murder for the deaths of his own parents.

Investigators say they found the bodies of Blake and Mary-Jo Hadley Sunday, around 4:20 a.m. after a "welfare check" following a tip that a crime had been committed.

Neighbors say the 17-year-old hosted a party with dozens of other teenagers Saturday evening into the early hours of Sunday.

Police say party guests probably didn't know the bodies were in the house.

A 22-inch hammer was found between the bodies. It is believed to be the murder weapon.

It could be speculated that perhaps the father was the first one that was murdered and the mother shortly after that.

Police describe the teen as "nervous" and that he lied to them during questioning.

Tyler Hadley is in custody and being held without bond.