Aburto said she was surprised by Richard Forsberg's explanation that his wife was staying with friends in Arizona.
"I thought, 'Arizona?' I didn't know she knew anyone there," Aburto said.
It also disturbed her when she saw him driving his wife's car instead of his own.
"When I saw him driving her car I knew something was wrong," she said. "He's been driving it for a couple of months."
Finally, on Monday, Aburto called police to report the woman missing. She said what made her decide to do it was receiving a letter from a good friend of Marcia's, Cathleen Deremeer, who said she had not been able to reach her.
She called the police as soon as she spoke with Deremeer.
Investigators spoke with Richard Forsberg on Tuesday, but he has since vanished.
"There's been no cell phone activity on his cell phone," Amormino said. "Needless to say, there's been no cell phone or financial transactions on Marcia's, the missing person."
Investigators searched the Forsbergs' home and have seized Richard Forsberg's car.
He is believed to be driving his wife's car, a silver 2001 VW Beetle with California license plate 4TIM403.
The Orange County Sheriff's Department is asking anyone who sees either of the Forsbergs or the car to call (714) 628-7170.