An Oakland man who allegedly attacked his girlfriend’s twin toddlers with a plastic bat in May pleaded not guilty to the crime on Tuesday.

David Devine, 25, faces two counts of aggravated assault for an alleged May 11 attack on Brooklyn and Maddilyn Walker, 2 years old, the daughters of his girlfriend, Emily Walker.

He remains in custody at the Kennebec County jail on $50,000 cash, according to District Attorney Maeghan Maloney.

Devine’s next scheduled court appearance is Oct. 7. It is possible the case will go to trial, said Maloney.

Devine is accused of seriously injuring the girls while their mother was at work. Walker said she came home to find one girl with a broken leg and the other with a broken arm, among other injuries.

They were initially taken to Inland Hospital in Waterville and then taken by LifeFlight helicopter to Eastern Maine Medical Center in Bangor.

Devine told police at the time that the injuries were caused by Walker’s four-year-old son, who was home at the time. However prosecutors said after his arrest that the injuries were so severe that there is no way they could have been caused by a boy of that age.

Before the twins were injured, Walker had planned to marry Devine, she told the Morning Sentinel after the attack.