Amanda Peterson, who starred in the classic ’80s film Can’t Buy Me Love opposite Patrick Dempsey and Seth Green, was found dead in her Colorado home on Sunday after failing to show up for a meeting, and now her mother has spoken out about the tragedy, revealing what she believes to be the cause of death.

Sylvia Peterson says she thinks Amanda’s sleep apnea may have been at the root of the problem, although an autopsy is still pending, and noted to People Magazine that her daughter’s death came as a shock to everyone. Amanda had been gardening earlier in the day with her mom and seemed fine.

“She was in bed, and she’d had a wonderful day, and we were planning on a dinner the next day, so it was just a very, very big surprise,” Sylvia said.

Sleep apnea is a condition in which a person’s breathing stops and starts during sleep, which can lead to serious heart problems or death. It’s unclear whether Peterson was receiving treatment for the condition.

Amanda Peterson was most well known in Hollywood for Can’t Buy Me Love, but she also starred in Explorers and made appearances on Doogie Howser, M.D. and Silver Spoons. Her last film was Windrunner in 1994; after that, she retreated to Colorado to focus on continued education and raising a family. She was reportedly working on an autobiography, as well, something fans would have been ecstatic to read. For many, Amanda’s performance in Can’t Buy Me Love turned the film into an instant classic and either led to a crush or the desire to be that cool girl in the leather fringe jacket.

“She went back to school, but she did not ever go back to Hollywood. She lived in Greeley and she lived in Fort Collins, and pretty much just continued in graduate work and in studying in that kind of thing. She was very involved with her church work,” Sylvia Peterson said.

Amanda Peterson is survived by her husband and two children. She was 43 years old.