State Police say Arnold Diana, 35, of Rockland used to be the boyfriend of Katrina Windred, 47, of Friendship. State Police also say he killed her. Diana was in court today in Rockland.According to court documents, Diana told police he met with Windred on Saturday, November 20th. Diana says she and her son were dropping off some groceries off at his apartment on Main Street in Rockland. Windred’s 9 year old son stayed in the car, according to the affidavit.Diana told police Windred asked him where he was having Thanksgiving. He said a woman’s name, and that’s when Diana says Windred got upset and pushed him. Diana told police he became angry, grabbed her, possibly by the neck. She fell to the floor, and he was on top of her. Diana says she was not conscious but she was breathing.Court papers say Diana then took Windred to his bed and put her face down in a pillow, a pillow that was later found by police in a garbage bag under Diana’s bed. The State Medical Examiner confirmed Windred’s cause of death was asphyxia due to strangulation. Diana told police he took Windred’s ATM card, then took her son and went to the bank. Diana withdrew $60 with that card. Diana said the two then went back to his apartment. After her son went to sleep, Diana said that’s when he found out Windred was dead. Diana admitted to police he wrapped Windred’s body in the blanket she was covered with on his bed. Diana said he then dragged her body to a truck and dumped it along the Thompson Meadow Road. On Sunday, November 21 court documents indicate Diana brought Windred’s son to her ex-husband’s house in Friendship. Diana does have a criminal history that points to violence. Last year he was convicted of assaulting another girlfriend. Records state she required staples to treat a head injury sustained from Diana. Diana has been ordered to undergo a mental exam and a bail hearing has been set for next week.