SAN BERNARDINO, Calif. (KABC) -- It's been nearly nine years since the McStay family disappeared from their Fallbrook home without a trace.
On Monday, the man accused of killing the family stood as jurors entered a San Bernardino County courtroom as opening statements in the murder trial got underway.
The prosecution laid out the case for jurors, explaining to them that by the end of the trial they would learn the how, the who, and the why of the murder case.
"The how is they were beaten about the head and face until they died, and then they were taken 100 miles away from their home and buried in the desert," said Sean Daugherty, San Bernardino County deputy district attorney.
Charles "Chase" Merritt has pleaded not guilty to the murders of Joseph McStay, his wife Summer, and the couple's four and three-year-old sons.
The prosecution says Merritt was McStay's business partner and that he killed the family out of greed.
"While claiming to be Joseph's best friend, he was forging checks from Joseph's business and taking money from him. Putting his hands in the cookie jar," said Daugherty.
In November 2013, the remains of the McStay family was found by an off-road motorcyclist. Jurors listened to an audio recording of the 911 call.
"Hi, I'm out here on a motorcycle behind the dump and I found what looks like a human skull," said the unidentified caller.
The skull fragment belonged to 3-year-old Joseph Mateo McStay Junior and is one of only a few remains found of the child. His four-year-old brother, Gianani was found in a grave with his father.
Summer McStay's remains were discovered in another shallow grave beside them along with a three-pound sledgehammer.
"All four members of the McStay family were killed by blunt force trauma to the head," said Daugherty.
The prosecution said evidence found at the McStay's home, the gravesite, cellphone records and financial records point to Merritt.
The defense refuted the prosecution's evidence, casting doubt on the timeline of the murders and the DNA evidence collected from inside the McStay's SUV.
"This isn't a murder. This isn't a case about a murder. Murders happened every day. This is a case that somebody wanted this family to disappear," said defense attorney, James McGee.
They also questioned the prosecution's evidence.
"From our perspective the prosecution we can tell from their opening it is based on innuendo, rumor, circumstantial evidence," said defense attorney Rajan Maline.
The defense said there was also evidence based on how Summer McStay's clothing was found that she was raped at the scene. Summer's sweatpants and underwear had been removed together and found bunched up by her head.
They also said evidence shows the crime could not have been carried out by one man alone.
"Just the two graves alone tell you it is two teams. If you are one person killing four people and bury them, you are going to dig one hole," said McGee.
The prosecution contends the family was murdered on Feb. 4, 2010 inside their Fallbrook home.
But the defense says there is no evidence to support that claim since no blood evidence was found in the home.
"There would be blood everywhere," said McGee.
The defense wrapped up its opening arguments by pointing to another potential suspect. They say McStay had another business partner with motive to kill the family.
The trial will resume Tuesday morning.
McStay family murders: trial underway in infamous IE case