Aston woman fatally stabbed boyfriend with a steak knife during an argument, police said

An Aston woman has been charged with first- and third-degree murder after police say she stabbed her longtime boyfriend in the chest with a steak knife during an argument late Monday.

Beth Peterson, 35, told officers who responded to her home on Blackthorne Lane that she “ruined her life” by stabbing Matthew Wilcox, 39, whom she had been dating for eight years, according to the affidavit of probable cause filed in her arrest.

Peterson remained in custody Tuesday, denied bail. Her lawyer, John Rooney, did not immediately respond to a request for comment.

Officers found Wilcox lying on his back in the kitchen of his home with a single stab wound in his chest, the affidavit said. He was taken to Crozer-Chester Medical Center, where he was pronounced dead. A steak knife was found, discarded, in the kitchen sink nearby.

During an interview with police, Peterson said that Wilcox had returned home drunk hours earlier, and that she had called his mother to come over to help mediate an argument between the couple. After Wilcox’s mother left, he attacked Peterson, she said, and she stabbed him with the steak knife, according to the affidavit.

Wilcox’s mother later corroborated parts of Peterson’s story to investigators, saying that she often had to defuse disputes between the couple. She called their relationship “toxic,” the affidavit said, and said she had previously seen signs of physical abuse on her son’s body, which he told her had come from Peterson.

She had also overheard Peterson say that she wished her son “was dead or got into a car accident,” the affidavit said.

Still, she told police that she had never heard her son threaten, nor observed him attack, Peterson, according to the affidavit. On the night of the stabbing, Wilcox’s mother said she talked to her son about his alcohol abuse at Peterson’s request, and that, though her son was argumentative, Peterson did not appear to be scared or worried about her safety.