Perez said investigators discovered Mason was malnourished, suffered continuous physical abuse, and was forced to live in a shed in the backyard of Jackson’s home.
Hayward Police was called to a “report of an at-risk missing juvenile” on March 8 by a family member, who was not identified in statement. Detectives began investigating the disappearance of Mason and, within two days, arrested Mason’s mother Samantha Johnson after “it was determined” there was probable cause for “corporal injury on a child,” said Hayward officials.
“Merced PD has since added a murder charge against Johnson, in addition to the corporal injury and obstructing an officer’s investigation charges filed by Hayward PD,” said the Hayward city statement.
The manhunt for Jackson began not long after authorities charged Johnson, Perez said.
“Detectives acted on evidence quickly to track Jackson’s location but he had the help of several people to assist and to elude his capture,” Perez said.
According to Perez, hundreds of hours of analyzing and deciphering electronic forensic data was “huge,” to the case. Police also utilized more than 20 search warrants to help obtain evidence related to the case, Perez added.
Jackson also had several female acquaintances who provided him with money, shelter and transportation to help him hide, Perez said. Those women have since been charged, Perez added.
Perez said all the hard work “finally paid off” when authorities found Jackson in Newark, California, on Saturday and took him into custody.
Jackson was arrested Saturday in Newark after a months-long search and an investigation led by the Merced Police Department with assistance by the Merced Area Gang and Narcotic Enforcement Team and the Department of Justice’s Special Operations Unit, according to Bonta’s office.
It is unclear if Jackson has an attorney at this time. CNN has reached out to the Merced County public defender’s office for more information.
“In my 20 years of law enforcement, this case is the most disturbing and horrific, I’ve seen. To know what that poor little angel went through by the hands of pure evil, breaks my heart,” Perez said, while standing next to a photo of Sophia.
Bonta, who was also present at the news conference on Sunday, thanked all of the departments that worked to capture Jackson.
“Let today serve as a reminder: When a horrendous crime like this is committed, we will leave no stone unturned to secure justice. We will keep pursuing you, until you are caught,” Bonta said.
CNN’s Colin Jeffery and Melissa Alonso contributed to this report.