Palmer's body was discovered inside Golden Sun Sales office in Stanton, a business that sells manufactured homes. She worked there for years as a secretary.
Matthew Francis Scott, a 42-year-old salesman, was also found fatally shot in the office. Their bodies were discovered by Scott's father.
Elizabeth Palmer's white Lexus GS300 was stolen at the time of her death. Detectives located the vehicle this past Sunday in a back parking lot of the El Dorado Inn in Anaheim.
Investigators have been looking for Palmer's Lexus since the killings. They say now that they have found the stolen vehicle they can move forward in the investigation.
"I call it a major break in the case. Now we have the vehicle," sheriff's spokesman Jim Amormino said. "Hopefully someone will come forward and give information to the sheriff's department to who may have parked the vehicle here."
Investigators have been handing out flyers door-to-door at the complex hoping someone saw something.
"I've noticed the car parked there before," said a witness. "I've seen it parked in different spots though."
Authorities say the car is in good condition, the ignition is not punched. The license plates have been replaced with paper ones from South Bay Toyota.
Investigators hope they'll uncover fingerprints or other evidence once they take a closer look inside at their forensics lab.
So far, detectives still have no motive for the murders. The business did not keep any money. Authorities have not ruled out the two were targeted for some reason.
There is a $75,000 reward being offered for information leading to an arrest in the case, Amormino said.