PLYMOUTH, Conn. (WTNH) — A woman is in serious condition at Waterbury Hospital after being mauled by her four mastiffs on Monday.

Related: Woman attacked, seriously injured by her own 4 mastiff dogs in Plymouth

According to police, the attacked happened in a yard on Eastview Road — the Terryville section of town. Officers said the dogs were loose in the yard.

Reports state a witness saw the attack and called 911.

When officers arrived, they said the dogs were on top of the woman and were still acting aggressively.

After separating them, officers shot at the dogs and killed three of them. The fourth dog is being quarantined by animal control.

The department said school was letting out around that time and officers feard the dogs would attack children nearby.

Reports state the dogs did belong to her. It is unclear what caused the attack.

“It was a complete mauling,” said Sgt. Randy Foster. “It appeared that four of the mastiffs that were there took part in the attack.”

Officers have not released the woman’s identity.

An investigation is ongoing.