Samuel Lopez murdered his former high school sweetheart Cathy Torrez

It was a murder that shocked the tight-knit community in Placentia, California. In 1994, 20-year-old student Cathy Torrez was reported missing. A week later, her remains were found in the trunk of her car; she’d stabbed to death.

Her murder remained unsolved for 20-years until justice finally caught up with Cathy’s former high school sweetheart, Samuel Agustin Lopez.

Lopez and Cathy had dated in high school, and there were hopes that the two were about to renew their relationship. Several days before the murder, Lopez had suggested that they elope together, but Torrez turned him down, saying she wanted a proper wedding.

However, it all went very wrong when Lopez spotted a hickey on Torrez. Investigators believe that Lopez was prone to bouts of jealously and that he flipped into a rage on seeing that hickey.

Torrez tried to flee from Lopez, but he caught up with her and stabbed her about a dozen times. He then flung Torez into the trunk of his car, where he slashed her neck and wrists. It was these wounds that killed the Cal State Fullerton student.

The police were suspicious of Lopez, even before his girlfriend’s remains were discovered, as he seemed unconcerned as to her whereabouts. Unfortunately, they had no evidence to tie him to the crime, so the case went cold.

Advances in forensic science finally brought Lopez to justice

Luckily advances in forensic science, particularly in the tracing of DNA and fingerprint evidence, meant that the cops were eventually able to zero in on Lopez, and in 2007 they made an arrest.

The DNA had pointed to Lopez’s cousin Xavier Lopez who police now believed had helped to shove Torrez in the car trunk. It would later transpire that Lopez’s brother Armando Lopez had also been involved in covering up the crime.

In March 2015, Lopez finally went to trial and was found guilty of murder. A couple of months later, he was sentenced to 26-years in prison.

At the sentencing, he suddenly made a surprise confession and issued an apology.

“It was all my fault,” Lopez said. “Everything that Mr. [Deputy District Attorney Matt] Murphy said is true. I do hope and pray this brings at least a small amount of relief from the pain I have caused them. This was a horrible act that never should have happened.”

Xavier Lopez pleaded guilty to manslaughter and received nearly 5-years in prison, whereas Armando Lopez was put on probation for his part in the murder.

More from Investigation Discovery

Follow the links to read about more crimes of betrayal and murder profiled on ID.

Earnest Hargon, described as a modern-day cowboy from Mississippi, massacred his cousin Michael Hargon with his wife and young son, over a dispute involving inheritance.

In Florida, in 1986, Gary Troutman approached a former classmate, the pregnant 24-year-old Angela Savage, and her 6-month son, and raped and murdered her. He left her splayed on the road and her infant son on a neighbors porch.

My Family’s Deadly Secret airs at 10/9c on Investigation Discovery.