A Colorado woman has been charged with first degree murder after allegedly stabbing her mother to death in an argument.

Police found Sarah Riste, 37, and a young child sitting outside their Westminster home on September 28 after she called 911, the Denver Post said. Riste told officer there had been an “accident” and let them inside, where they found the body of 64-year-old Kathy Johnson beneath some blankets in the hallway.

Police said they saw a large amount of blood on the walls.

An affidavit said that police also saw Riste yelling at the child, telling them not to speak. She was seen with blood on her shirt and hands, an affidavit said.

During an interview, Riste said she had gotten into an argument with her mother and, because of years of emotional abuse, she grabbed a knife from the kitchen when the argument turned physical.

According to the affidavit, the child told investigators “something to the effect of: mom stabbed grandma, mom is going to jail, grandma is dead and now I don’t have anyone.”

Westminster Police said the child was turned over to Child Protective Services.