Wendy Byron lived in the house with her husband, Robert. She disappeared in August 1978 at the age of 24. Her car was found abandoned at the airport in Ontario. Foul play was suspected.
The digging began around 8 a.m. and went on until dusk. However, investigators said they did not find evidence of a body in the backyard. They said they would return to the scene Thursday morning.
People familiar with the disappearance remain skeptical.
"The husband is always one of the first ones you consider a suspect, so yes, he was a suspect. He said he'd been through a lot with the police," said Margie Green, who claims to know the husband well.
"He acted like he was hurt she had disappeared, left him, or whatever," Green said. "He did say they had a bit of an argument, so when he came home and she was not there, maybe he thought that she was just mad at him and she just never came back."
Robert Byron's sister said he told the family that Wendy Byron had moved to Ohio and changed her identity. Byron also said he spoke with his wife years after her disappearance, but nobody from the family had ever spoken with her.
Robert Byron left the home, re-married and now lives in Covina. He did not return messages seeking comment.
Investigators would not say if conversations with Byron or someone in the disappeared woman's family prompted the new search. They also said the current homeowners did not have anything to do with the case.