DENVER (AP) — A Denver couple accused of keeping four malnourished young children in a filthy apartment pleaded guilty to neglecting three other children under strikingly similar conditions in 2006, court records show.

The parents, Wayne Sperling and Lorinda Bailey, appeared in court Tuesday on felony child-abuse charges. Authorities say their four boys, ages 2 to 6, lived in a rank-smelling apartment littered with cat feces, flies and urine. The boys could not speak and only grunted, authorities said.

Police found similar conditions at the couple’s apartment in 2006, when they had three other children, records released Tuesday show.

All seven kids were placed with a child services agency. No other details were available on their current status or whereabouts.

Bailey, 35, is free on bond. She declined to comment after leaving court Tuesday.

Sperling, 66, is still in custody and appeared in court with his long white hair in a ponytail and wearing a long, flowing beard. His attorney made no public statement.

Neighbours said they repeatedly complained to authorities about the boys’ care but nothing happened.

Police said the children found in 2006 were dirty, wore unwashed clothing and had not been fed for several hours. The oldest, age 4 at the time, spoke few words and mostly grunted and pointed to communicate, the records show.

Passers-by called police in the 2006 case to say a 2-year-old and a 4-year-old were playing in the street. Officers said they found rotten food, trash and insects in the apartment.