A Westport couple arrested for allegedly hurting their 6-month-old foster child and not caring for three other foster children in their care pleaded not guilty to assault and risk of injury charges Thursday in Norwalk Superior Court.

Debbie DeCarvalho, 42, and Mario Leone, 38, of 1040 Post Road East, made the pleas before Judge Bruce Hudock.

The two were arrested on first-degree assault charges Jan. 19 following a six-month Westport police investigation after the couple brought a 6-month-old boy into the Norwalk Hospital emergency room in early July.

The boy had bleeding on the brain and a possible skull fracture that could have been caused by shaken baby syndrome, according to arrest warrant affidavits.

Leone's defense lawyer, Joseph Colarusso, said it is too early to comment because he has not seen the baby's medical records or talked with others associated with the case.

"My client steadfastly maintains his innocence," he said.

DeCarvalho, kennel manager and pet stylist at Town House for Dogs and Cats at her Post Road East address, told investigators the baby, which had been in her care for three weeks, had not fallen or experienced injuries to the head.

Leone, however, told police at one point during the short time they had the child, the baby accidentally fell off the couch and landed on his back.

DeCarvalho's lawyer, Vicki Hutchinson, said her client maintains she did nothing to harm any of the children in her care.

When staff from the state Department of Children and Families interviewed the three other children in their care, they said that DeCarvalho paid little attention to them while attending her pet-grooming business. The children, however, said they never saw DeCarvalho or Leone mistreat the baby.

DeCarvalho was charged with three additional counts of risk of injury to a minor as a result of those interviews.

DeCarvalho and Leone are to return to court Feb. 25.

After turning themselves over to police, DeCarvalho was released on a $50,000 cash bond and Leone was released on a $25,000 cash bond.