A passerby made the discovery around 9:10 p.m. at the parking structure of an apartment complex on the 2100 block of Scholarship.
"They saw a subject slumped over in a car and called the police. When we arrived we found that there were actually two subjects in the vehicle and that they were deceased," said Irvine police Lt. Julia Engen.
Police said the victims, 27-year-old Keith Lawrence and his fianc?e, 28-year-old Monica Quan, were found shot to death in Lawrence's car. The couple lived in the apartment complex.
The deaths are being investigated as a double-homicide, not a murder-suicide. Investigators said it appears the victims were shot inside the parking structure. But at this point, no residents have reported hearing any gun shots. Nothing was stolen from the car.
"You know, you hear lot of loud noises in a garage and echos, so maybe it didn't catch anybody's attention," said Dan Trznadel.
On Monday night, dozens of people gathered for a candlelight vigil at Walnut High School, where Quan was a student athlete.
Lawrence and Quan graduated from Concordia University in Irvine, where they both played basketball. Lawrence graduated with a business administration degree, while Quan received a master's degree in coaching and athletic administration. She was in her second season as an assistant coach for women's basketball at Cal State Fullerton. Lawrence started working as a public safety officer with USC in August.
None of the residents who spoke to Eyewitness News said they knew the victims, but some did say they have been worried about the building's security. Access to the apartment's parking structure is supposed to be controlled though keycards and codes, but residents say it isn't difficult for anyone to get inside.
"We've been having some smash-and-grab break-ins for about two years," said resident Nick Chapman. "My car got broken into, my wife's car got broken into."
Chapman says he has asked the building to put up surveillance cameras in the past to deter petty crime, but now he feels the security need even more.
"We're definitely going to watch over our shoulder a little bit more," he said. "You certainly don't want to have to be concerned for safety where you live."
"It goes to show you it can happen anywhere," said resident Dan Roseman. "Irvine is a great, safe city, but these things can happen."
Cal State Fullerton sent its condolences to Quan's family and the university on Monday.
"The loss of any member of the Titan family causes our community great grief, but the loss of one of our own under these circumstances is indeed tragic and heart wrenching," Jeffrey D. Cook, the university's chief communications officer, said in a statement. "We hope that Monica's family and friends will feel and be comforted by our support during this difficult time."
Cook also said the university will provide counselors for students and staff.
Investigators do not have a suspect description or motive. Anyone with information was asked to call Irvine police at (949) 724-7000.