DES MOINES, Iowa (AP) — An Iowa teenager testified at his mother’s murder trial that she forced him and his two sisters to sleep on their bedroom floor in their own waste for months and that she refused to feed one sister in the days before she starved to death.

The Des Moines Register reports that the 16-year-old told the Polk County jury on Wednesday that his sister Natalie had become too weak to get up to eat, but their mother told her she wouldn’t help her.

Nicole Finn was charged with murder, kidnapping and child endangerment after Natalie Finn died in October 2016 at the age of 16. She’s also accused of abusing the son who testified and her younger daughter. Investigators say they were severely malnourished and living in squalor in the family’s West Des Moines home.