A Missouri man has pleaded guilty in the fatal beating of his 77-year-old grandmother while he was drinking alcohol and taking prescription drugs.

Robert Forrester pleaded guilty Friday to second-degree murder in last September’s death of Beverly Forrester of St. Joseph. The 29-year-old grandson faces up to life in prison when he’s sentenced later this year.

Robert Forrester told the judge he had been drinking whiskey and was on sedatives when he attacked his grandmother at her St. Joseph home.

The grandson said he remembered killing the victim but did not feel emotionally present during the attack.

ThinkStock