Emmanuel Jigba, a Sierra Leone native now living in the San Jose, California, area, was in Tempe Thursday trying to find his son, Willie Jigba.
Jigba was last seen at a party in the 600 block of East Weber Drive in Tempe early Saturday, and hasn't been heard from since.
Tempe police spokesman Sergeant Steve Carbajal says officers have been actively searching for Willie since he was reported missing.
Jigba's friends and family also are concerned that as he walked home from the party, he may have fallen into Tempe Town Lake, which he probably would have passed in the 2 1/2 miles to his apartment.
Carbajal said the lake was searched from the air and on the ground, but it wasn't yet clear if it would be scoured more closely by detectives.
"Investigatively I don't know where that's going to go," Carbajal says. "We don't have any evidence that he's in the lake."
He says police also have been monitoring his Internet and financial accounts, which haven't shown activity since his disappearance.
The elder Jigba says he's meeting with his son's friends to help look for him, and that he would stay in Tempe until Saturday, or longer, if need be.
"For him to be away for two days or three days ... it's not like him," he says.
Jigba is described as about six feet tall and about 190 pounds. He has black hair and brown eyes.
Anyone with information about Jigba's whereabouts is asked to call the Tempe Police Department at 480-350-8311.