Investigators are targeting transient campgrounds in the hunt for clues to the slayings of a pregnant woman and her husband in a Southern California beachfront home.

Ventura County sheriff's Capt. Ross Bonfiglio says about 35 volunteers have been helping investigators Friday in the search of bushy, wild areas near the home of Brock and Davina Husted.

The couple, both 42, were stabbed late Wednesday by a man who barged into their home dressed in black and wearing a motorcycle helmet.

The Husteds' 9-year-old son and 11-year-old daughter were home but were not harmed. They are staying with relatives.

Davina Husted was four to five months pregnant.

Bonfiglio says the investigation is ongoing.