Police and family members are asking for the public’s help in the desperate search for a 22-year-old PhD student at the University of Southern California.

ABC 7 reports that Bo John Jones disappeared after leaving his Los Angeles apartment late Sunday afternoon, presumably for walk in nearby MacArthur Park. Jones reportedly took his cell phone with him, but left his wallet behind.

An unidentified woman found the cell phone Thursday at a playground in the park, and brought it to a cell phone retailer to try and open it. Jones’ parents had activated the “Find my Phone” feature by that time, and were alerted that it had been turned on.

The missing young man’s parents traveled to Los Angeles after learning from their son’s roommate that he had not returned home on Sunday.

“He’s very responsible and everything. For him to just walk away, leave his car, his wallet, his ID – just to leave it here at the apartment and just walk away is not like him,” James Jones, Bo John’s father, told ABC 7.

His mother Susan Jones said Bo John was in good spirits when they last spoke.

“He sounded great. He was happy. He was looking forward to coming home to New York at the end of the month,” the mother told the news station.

“We’re all wracking our brains trying to figure out what could have possibly happened because it’s not like him at all.”

Bo John Jones is a caucasian male with brown hair and blue eyes. He is 5 feet 7 inches tall with brown hair and blue eyes. He was last seen wearing grey shorts and sandals with a red USC T-shirt.

Anyone with information about Jones’ whereabouts is urged to contact the LAPD’s Missing Persons Unit at (213) 996-1800. On weekends and after hours, calls should be directed to (877) 527-3247.