The mystery behind the mysterious disappearance of a California family more than four years ago ended Saturday when a man was charged with their four murders -- the parents and their two young sons. The man was a business associate of the father.

The remains of Joseph and Summer McStay and their two boys were discovered in the deserts near the U.S.-Mexico border last year. This reinvigorated the investigation of the San Diego family's case. Police announced that they made an arrest for the killer Saturday.

The Associated Press reported that the man, Charles "Chase" Merritt, knew the family through business and was expected in court for the four murder charges he faces later in the weekend.

The San Bernardino County Sheriff's office said that all of the victims died of blunt force trauma. The sheriff added that the remains of 40-year-old Joseph, Susan, 43, and their 3 and 4-year-old sons Joseph and Gianni were found in November 2013. The bodies were discovered intact and clothes were found in the graves, but there was no further details on what items were found with them.

The McStay family vanished from their home in San Diego in February 2010, but there were no evidence of a break-in. However, other signs like rotting eggs on the kitchen counter and their two pets in the backyard, indicated that the family left suddenly. The family's car was found parked near the border off Interstate 15.

Over the year following the discovery of the bodies, police issued 60 search warrants and conducted over 200 interviews trying to find someone connected with their deaths. There was even surveillance video of a family of four crossing the border on foot just after the McStays were reported missing. It is still unknown how they died or for what reason.