When a family of four vanished without a trace in 2010 months after moving into a new house in the San Diego suburb of Fallbrook, California, it looked like a missing-persons case. There were no bodies and no answers.
Three years later, in November 2013, a motorcyclist stumbled upon a skull in the Mojave Desert and called investigators who, soon after, uncovered two graves.
The McStay family had been found.
But what happened to Joseph McStay, 40, his 43-year-old wife, Summer, and sons Gianni, 4, and Joseph Jr., 3? Authorities think they’ve caught the killer, who is awaiting trial, and the family has a theory about motive.
Here’s what to know.
1. The McStays Seemed to Have Suddenly Disappeared
On Feb. 9, 2010, Joseph’s father, Patrick, received an email from a business partner of his son’s saying that he hadn’t heard from him.
The following day, Det. Troy DuGal from the San Diego County Sheriff’s Department checked on the two-story home where the family lived. He found no sign of foul play in the empty residence, only evidence of a family’s everyday life: paint cans in the kitchen that they were renovating, a carton of eggs on the counter and two small bowls of popcorn on the futon in the living room.
“That’s weird,” DuGal later recalled thinking. “It was like two kids were sitting there eating popcorn, and then they were just gone.”
The family’s two beloved dogs, Bear and Digger, were left behind in the backyard, and nearly $100,000 remained untouched in Joseph’s bank accounts (he ran a successful decorative-fountain business).
Said Joseph’s younger brother Michael, “It’s just not like them to walk out on a business, walk out on money, walk out on a home.”
“It doesn’t make sense,” Lt. Dennis Brugo from the San Diego Sheriff’s Office told PEOPLE in 2011. “When you have people drop out of society, it’s usually for a reason — they’re having money or family problems. In this case, it looks like they were planning for the future.”
2. It Took More Than 3 Years to Find the Bodies
The McStays’ whereabouts were finally confirmed when a motorcyclist riding through the desert above Victorville, California, came across a weathered skull and called police in November 2013.
That discovery led to two shallow graves containing the remains of Joseph, Summer, and sons Gianni and Joe Jr.
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3. Ex-Business Partner Was Charged in the Killings
After the McStay family went missing, Patrick wanted to speak to his son’s friends — even if it meant possibly speaking to the killer.
He had a list of people he thought could have harmed his son and his family. One of the names was Charles “Chase” Merritt, a former business associate who worked with Joseph and helped with his company.
“I didn’t have proof and I didn’t know it was definitely him,” Patrick told PEOPLE in 2014. “I had direct contact with him, so I had to try and keep that contact open to see what I could find out.”
Patrick’s suspicions were validated when Merritt was arrested on four counts of murder in November 2014.
“It’s all about money,” Patrick told PEOPLE after Merritt was taken into custody. “That’s what I believe.”
4. The Killings Were Brutal
During a preliminary hearing in June 2015, detectives testified that Joseph’s body was found with a white extension cord wrapped around his neck. Summer’s skull was fractured and one of their sons’ heads was bludgeoned seven times, according to testimony.
A sledgehammer was also found buried at the site.
Additionally, detectives testified that DNA matching Merritt was found on the steering wheel of the McStays’ white Isuzu Trooper, which was found abandoned near the Mexico border days after their disappearance.
5. Suspect Maintains His Innocence
According to the San Bernardino Sun, prosecutors allege Merritt was a gambling addict who committed the crime for financial gain and wrote thousands in checks on Josephs’ business account for days after he disappeared.
The trial has been delayed due to Merritt’s failure to retain an attorney. As of February 2016, he had reportedly gone through five attorneys and attempted to represent himself in court twice.
Merritt, who has pleaded not guilty to the four counts of murder he faces, is eligible for the death penalty should he be convicted. He remains in jail without bond and will stand trial for the killings in early 2018.
His attorney, who could not be reached for comment by PEOPLE this week, has previously told reporters there is no evidence that links his client to the slayings.