James Wernke, 21, was last seen in Fullerton, Calif., Saturday afternoon as he leashed up a friend's Labrador retriever for a walk. Neither he nor the dog have been seen since.
"Not one lead," Fullerton Police Lt. Alex Bastreri said. "I wish we did."
One of the few pieces of information authorities have to work with, he said, is that disappearing without a trace is extremely out of character for Wernke.
"He's always happy, he's always smiling," Sheri Wernke told ABCNews.com, her voice cracking at times as she spoke about her son. "So this is just the most bizarre thing."
Wernke, who flew in from Colorado on Sunday along with her husband, said her family is very close, talking to each other several times a day. For even a day to go by without word from James is extremely unusual, she said.
"That's what police were saying, it just doesn't fit any profile" of a missing person, Sheri Wernke said.
Family and friends papered the Fullerton area with 1,500 flyers Sunday, she said, and bloodhounds were sent out to track both Wernke and Kealie. Sheri Wernke said the bloodhounds tracked them to a 7-11 store about a mile away before losing the scent along a major road.
"The only thing we can think of that makes any sense ... did he fall in the rain and hit his head?" Wernke said.
Bastreri said search teams are out on foot and on all-terrain vehicles on the many horse trails in the area and are paying close attention to shrubbery or wooded areas where Wernke may have fallen and laid undetected.
They are also hoping to review the tapes from the 7-11 store by the end of the day in hopes Wernke will show up in some of the frames.
"It's a shot in the dark," Bastreri said.
Wernke went to the gym around 11:30 a.m. on Saturday and talked to his mother around 1 p.m. Wernke, who lived about 20 minutes away from Fullerton in Orange, was a regular presence on weekend's at the home of Diana Bock, his girlfriend's mother, to do laundry and do homework.
Wernke and Sami Bock, a student at Long Island University in New York, were high school sweethearts who had been dating for about three years.
"They were so cute," Diana Bock said. "They're in constant communication. They text 24/7."
Around 2 p.m. Saturday Wernke set off with Bock's 2-year-old Labrador retriever Kealie. Sheri Wernke said it was raining and, they believe, he was clad only in shorts, a T-shirt and possibly flip-flops.
Bastreri said police were told that Wernke returned to Bock's house shortly after leaving and then took off again around 2:15 p.m., presumably with Kealie.
Leaving his wallet, license and his car at Bock's home, Wernke was only carrying his cell phone, which now seems to have died or been turned off, his mother said, preventing police from tracking the GPS signal.
His last known communication was a text message to his best friend at 1:44 p.m. Wernke said the friend sent him a message back, but James Wernke never responded.
Diana Bock said she began to worry after Wernke and the dogy had been gone for about three hours. She called her daughter Sami in New York to see if she had heard from Wernke , but she hadn't. After speaking with Sheri Wernke and waiting for several hours wondering if James Wernke had maybe taken Kealie to visit a friend, Bock called police around midnight.