In early mornings, before reason rises with the sun, Norma Hamilton, 74, longs for her boy.

“I wake up and wonder where he is,” she said.

The rest of the day, she thinks he’s probably dead.

But she and her husband, Bud, 75, don’t know for sure and haven’t since that January night 10 years ago, when Mitchell Hamilton hugged his father goodbye after watching a holiday bowl game, stepped into the cold darkness and disappeared.

A police Web site entry about him reads: “Subject left without explanation and was never heard from again.”

People vanish every day in America, often against their will. But experts say it’s not unusual for people to disappear voluntarily, to abandon lives molded by family, friends and career.

Some leave because of family conflict, stress, money woes or drugs. Some have found a new love that doesn’t fit into their old world. The owner of a private detective agency in California that specializes in missing-persons cases says she gets calls asking how to disappear and leave no trail.

The family members left behind suffer anguish — and typically insist to police that the missing person must have met with foul play. That may be true for many of the thousands of people listed as missing throughout the United States.

Some, though, simply walk out a door and are never heard from again.

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A murder investigation unfolding now in Cass County highlights the challenges facing police and the agony facing loved ones of those who have disappeared. After Michael Lee Shaver Jr. told authorities that he had killed as many as seven men during drug deals at a rural residence near Drexel, authorities sought the public’s help in coming up with names of possible victims.

They wanted to compile a list of people missing for several years, but all of those “missing persons” were found alive, content in their greener pastures, an investigator said.

Police can’t do much for families involved in such cases.

“It’s not a crime to go missing,” said Kansas City police Detective Jana Swann, who leads the department’s missing-persons unit.

Early on, Bud and Norma Hamilton, who live in Overland Park, held out hope that their son’s disappearance, too, was voluntary: Someday he’ll come back. But now, with hearts weary from a decade of hoping, their brains tell them their middle child probably is gone for good.

There is no shortage of cases supporting that belief. The “Missing Persons” cold case list on the Kansas City police Web site is pretty much a roster of people who, police believe, are now dead.

Police acknowledge that those on the list most likely are murder victims whose bodies have not been found: Gina Clark disappeared in 1991 after witnessing her boyfriend’s murder; the car of Shirley McKeown, with her blood splattered inside, was found covered with brush about two weeks after she went missing in 2002; Salvatore Manzo, missing since 1987, allegedly had ties to organized crime.

The list also includes the high-profile case of Summer Shipp, the Kansas City woman who disappeared in 2004 while doing a door-to-door marketing survey in Independence.

The vast majority of adult missing-person reports never get posted because the person usually shows up within hours.

“Monday morning is the big day for us — the weekend is over, and people forget where they live,” said Swann, the Kansas City detective. “They haven’t come home and they don’t show up for work.

“Well, to us, that’s not missing.”

Swann’s advice to callers is to be patient and check with other family members, friends and places of employment.

According to the National Center for Missing Adults, at any one time about 50,000 people are considered missing in the United States; an unknown number of those have disappeared voluntarily.

Some people who disappear on their own might never be located, said Chuck Stevenson, owner of Orion Investigations in Overland Park. They sever relationships. Get a new identity. Live a cash-based existence.

“They can’t change their DNA or fingerprints, but they can change everything else,” said Stevenson, a former FBI agent who is often hired to find people. “A person can build a whole new life for themselves, and if they don’t slip up, they won’t be found.”

Karen Stratton doesn’t think her daughter, Jody Ledkins, disappeared voluntarily. She prefers to believe that Jody, who was 14 when she vanished in 1985 from a Northeast area neighborhood, has amnesia.

Police suspect the girl was murdered.

No, Stratton said.

“In my heart and in God’s world, there is always room for a miracle, and that’s where this one will stay until I die,” Stratton said.

Swann said parents like Stratton and the Hamiltons are always the last to give up.

“They hold out hope — and as a parent you would have to,” she said.

•••

Bud and Norma Hamilton are most reminded of Mitchell during the happy times. Holidays, family gatherings, birthdays.

“We always think about him then … when we’re all together,” Norma said. “He is what’s missing.”

And a decade later, Bud, 75, still prays daily, “Lord, if he’s still living, watch over him.”

Mitchell’s sister, Kim Donald, said, “If I could be granted one wish, it would be that my parents find out what happened to Mitch, one way or the other, before they die.”

The case is unlike other cold case “missing persons” on the Kansas City Police Department’s Web site in that investigators do not suspect foul play in Mitchell’s disappearance. He was 37, much loved, a math wizard who was looked up to by his nephews. But he thought he was “fat, dumb and ugly.”

Police say Mitchell doesn’t seem to fit the pattern of voluntary disappearances, though he did suffer psychological problems. Family members say he had a chemical imbalance that caused him social anxiety and ruined his ability to hold a job. He fretted that he was a burden to his family.

“He thought we would be better off without him, and that just was not true,” Norma said.

Mitchell didn’t have friends of his own growing up, but he was close to his siblings, who looked after him, and he was sort of “adopted” by friends of his younger brother Jeff.

“He used to tell me how painful life was for him,” Jeff Hamilton said. “He was the nicest guy you’d ever meet, but he just couldn’t cope.”

Mitchell excelled at math and was great at computers. His father said he could sit down and work a 1,000-piece jigsaw puzzle “like a machine.”

But Mitchell struggled at Shawnee Mission South because of anxiety. College didn’t work out, either.

Later, after a series of failed jobs and a brief, troubled marriage, Mitchell lived with his brother, who had gone through a divorce and was raising two sons.

“Mitch was my boys’ Uncle Charlie from ‘My Three Sons,’ ” Jeff Hamilton said. “They loved him and thought the world of him, and they asked about him for years after he left.”

•••

Mitchell Hamilton would be 48 now if he were alive. His brother and sister do not believe he is.

“But my dad will go to his grave with hope that he’s out there somewhere,” Donald said.

For the first year or so, her phone would ring and the caller would hang up. She wondered if it was Mitchell.

“I guess I would like to think he was out there somewhere … good job, good family, and that he’s happy — I know that’s what my parents would like to think,” Donald said.

She said her mother and father had planned to move from the old neighborhood but put it off for a long time after Mitchell disappeared.

“They worried that he would come home someday and not be able to find them.”