King County Superior Court Judge Roger Rogoff today sentenced a man to 27 1/2 years in prison for the April murder of his 72-year-old aunt with a claw hammer inside her Bellevue apartment.

Mark Irwin was arrested on April 13, shortly after his aunt, Barbara Irwin’s body was discovered by a family member inside her Twelve Central Square apartment, her head caved in by a claw hammer.

The family member went to Barbara Irwin’s apartment after failing to reach her by phone, using a ladder to access the unit from an unlocked sliding door on the deck.

Mark Irwin was found with blood and scratches on his body, sitting in his aunt’s car about 100 yards from her residence, according to the police report. A man with Irwin in the car told officers the two men had smoked crack earlier in the day.

A family member told police his wife had spoken to Mark Irwin earlier, when he answered his aunt’s cellphone, and she suspected he was back on drugs. Mark Irwin had been staying with his aunt for several months.

Barbara Irwin was found next to her bed, which had sponges and cleaners on top. Blood-covered bedding was found stacked away from the door.

The King County Prosecutor’s Office recommended a sentence of 29 years in prison for Irwin, who pleaded guilty to second-degree murder in July.