By Madeline Holcombe and Joe Sutton, CNN

A gated community in Simi Valley, California, was evacuated Thursday after two people and a dog were found dead in a house and a bomb threat was discovered written on a wall, police say.

Police were called to the house around 6:45 p.m. after a man returning home from work found a woman and a lot of blood in his residence, Simi Valley Police spokesman Steve Shorts told CNN.

The woman was determined to be deceased when fire officials arrived, Shorts said. A man and a dog were then found dead of apparent gunshot wounds in the home. It is not clear if there is a relationship between the resident and the two people found dead.

Officials responding to the scene also found script writings on the wall indicating that there was a bomb in the residence.

The house was evacuated, along with 47 residents in the surrounding area, Shorts said.

No bomb was found, he said. The investigation is ongoing.