Officers drove to 432 Hightop Road on Tuesday, Jan. 2 because Calzadillas' loved ones had phoned in a welfare check, investigators have said.
Authorities arrived and saw 22-year-old O'Connor unresponsive on the floor through a window, while 41-year-old Calzadillas was found in a closet. Both were pronounced dead at the scene.
Police have not said which man killed the other, though they noted that no firearms were involved.
In charging documents filed in a Chester County court but later withdrawn, township police said they were called to the home by O'Connor months earlier on Sept. 9.
Calzadillas told responding officers that the fight started when O'Connor went upstairs to lock himself in a bedroom after an argument, the affidavit says.
Calzadillas said he followed and knocked on the door but received no response, according to the documents. He told police he kicked through the door and walked in the room — "in part to obtain his pet cat" — but that O'Connor punched him in the face several times when he tried to speak with him.
When the 41-year-old said he was calling 911, O'Connor allegedly took Calzadillas' phone and broke it, including smashing it against a wall and beating it with a hammer, the documents say.
O'Connor then went to an upstairs bathroom where he "attempted to strike his head" into the wall, the affidavit says. Calzadillas followed and wrapped the 22-year-old in a "bear hug" to stop him from hurting himself, police wrote.
The pair separated and O'Connor locked himself in a closet until authorities arrived, according to the documents.
A responding officer noted Calzadillas' face was swollen and bloody around the eyes and nose, and said he saw blood spattered throughout the house where the altercations took place.
Court records show O'Connor was charged with misdemeanor simple assault and related counts and was held before posting 10 percent of his $15,000 bail.
The charges were withdrawn after his preliminary hearing on Nov. 15.
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