WATERLOO - Like the death of Charles Michael Sires, the last years of his life remain a riddle with few clues.

In June, Sires, a one-time cancer researcher who went by "Mike," died much as he had spent the last years of his life - alone atop his bicycle and on the fringes of society.

The homeless hitchhiker was found dead between a garage and a storage shed behind a Waterloo home June 9.

When Mike Sires died this summer at age 57, many relatives hadn't seen him in decades. Some thought he had passed away years earlier.

He had severed ties with family, had no friends and kept to himself, according to family and police. He had no home; the address he had listed on his photo ID card was actually a business.

All his possessions he carried in his Jansport backpack.

"The most fortunate thing for us was that he died in a place where, No. 1, we know he's dead, and No. 2, my brother and I and the other family that's around could take care of him," said Don Sires, Mike Sires' brother in Oregon.

Police investigators looking into Mike Sires' death were faced the dilemma of trying to shed light on the final hours of a man who had been living in the shadows for years.

Officials said Mike Sires' death was recently ruled an accident.

But medical examiners were unable to determine what caused the fatal blunt injuries to his head, said Lt. Rich Carter with the Waterloo Police Department.

Carter said the wounds could also be the result of an attack - which would make the death a homicide - and he said detectives are keeping the case open because of the lack of evidence to point in either direction.

Modern-day Huck Finn

Growing up near the downtown John Deere plant in the 1950s and 1960s, Mike Sires was an athletic lad who learned boxing from his father and loved the outdoors.

"As a kid, when we'd come down in the morning, there would be two or three kids sitting and waiting for him because the adventure would start. He was kind of a modern day Huckleberry Finn," said Don Sires.

Mike Sires developed his own language at age 12. It was based loosely on the ape language of the Tarzan novels, which he devoured. He emulated the lord of the jungle in other ways.

"I've seen him run through trees and dive for limbs that he had no idea whether they would hold him or not. The guy was fearless," Don Sires said.

Don Sires saw that same fearlessness years later when Mike invited him to explore a cave near Carbondale, Ill., where he was working on his undergraduate degree.

The two had been crawling through tight passages for about two hours when Don couldn't help but wonder how his brother navigated the dark maze.

"We have rock on our stomach and rock on our back, and I say 'Gosh, Mike, how do you know how to get out of here?' And he looks at me and says, 'I don't know how to get out of here,'" Don Sires said.

Family members chalked up much of the adventurous and quirky behavior to Mike Sires just being weird and having fun.

"He was a geek," said Tom Sires, an older half brother whom Mike Sires had lived with in the early 1980s when Mike was working on his doctorate in molecular biology in Nebraska.

"A lot of Ph.D. candidates are that way," said Tom Sires, who is now a professor at the University of Nebraska in Lincoln. "A lot of the time their social skills aren't worth toot, and his social skills weren't worth toot. He was a macho geek, and that made him a little different."

Hints Mike Sires was suffering from mental illness began to show when he was in his 20s, Don Sires said.

Before going to college, Mike Sires had been in the U.S. Army. But the two weren't a good match, and he was discharged not long after boot camp.

There were failed marriages, and he also turned his back on his doctoral endeavors a few times only to return and pick up his research where he left off.

"Somewhere around 28, 29, things began to change, and I don't know what it was," Don Sires said. "A doctor friend of mine thought he might be a paranoid schizophrenic. It's really hard to tell. He had this dark side to him that just began to take over."

Mike Sires finally finished the course work for the degree and was working on his dissertation when he became involved in a dispute with his professor, Tom Sires said.

He said there were allegations someone had published Mike Sires' research under a different name. At any rate, the spat was the end of his life in academia.

"I think that was the trigger," Tom Sires said.

"He just walked away from everything after that," Don Sires said.

"We're all going to die"

Much of Mike Sires' visits in the years that followed were more like sightings.

Once he rode a bike from Texas to Nebraska to visit Tom Sires. He would occasionally show up in Oregon, where Don Sires had moved along with his parents and a sister.

At times both Don and Bill Sires, a brother in Waterloo, took him in, fixing him up with jobs and places to stay.

But it would never last, and his problems were starting to become more evident.

Once, Don Sires took him out to lunch when he noticed Mike Sires had become aloof during what had been a happy conversation.

When they left the building, Don Sires asked him what was wrong.

"He said, 'Did you see that woman across the restaurant? She was looking inside of me. She was trying to get inside of me and take my happiness. She's evil,'" Don Sires said. He said his brother accused people of being possessed on another occasion.

At one point, a driver stole Mike Sires' belongings after finding him hitchhiking on Interstate 80, said Bill Sires, a real estate agent in Waterloo. The driver picked him up and gave him a ride to a truck stop where he handed him a few dollars to get something to drink. When Mike Sires went inside the store to make his purchase, the driver took off, Bill Sires said.

Sometime after that, Don Sires found his brother living in a boxcar in the Portland area.

Then in 1987, when their father was dying, Don ran into Mike on the street by pure chance.

"I said, 'Our father is real sick, and I think he's dying.' He walked right past me like a ghost, going 'We're all going to die, man. We're all going to die,'" Don Sires said.

Mike Sires didn't attend the funeral.

Final day

It wasn't clear how long Mike Sires had been back in Waterloo before he was found dead.

Police believe he was wounded at an unknown location June 9 and then rode his Schwinn bike before finally collapsing near the shed behind 707 and 709 W. Park Ave.

He was found at about 6:50 p.m. after neighborhood dogs began barking.

A convenience store surveillance camera caught images of Mike Sires a few hours before his death, police said. He wasn't injured at the time.

After that, a witness reported seeing him bleeding as he rode his bike north on West Fourth Street, a short distance from where he was located.

Mike Sires' brothers said it appeared he didn't know how bad his wounds were and was looking for a place to stop and assess his injuries.

A shallow depression in the ground marks Mike Sires' last resting place in the Garden of Peace, which is a flat-marker section of Elmwood Cemetery.

The brothers paid for the funeral and burial. They are seeing if the government will contribute a headstone because of his military service.

During the service, a homeless man rode up on his bike to witness the ceremony.

"He thought nobody would be there for him," Don Sires said. "He didn't know him at all. I was hoping he did."

Family members prodded the unexpected mourner to try to understand what happened to Mike Sires. He related his own story - something in his life had "popped" and there was no going back.

"I think that's what happened with Mike," Don Sires said. "Something popped, and he could no longer live the life that all of us see as the regular life."

Contact Jeff Reinitz at (319) 291-1578 or jeff.reinitz@wcfcourier.com.

Don Sires gives us a look at his brother's mysterious life at {M7http://www.courierwebcasts.com/play.php?vid_id=421&file=jeffs.flv

The Waterloo Police Department explains how it solves mysteries at {M7http://www.courierwebcasts.com/play.php?vid_id=420&file=arends.flv

A mother shares her story and fears about being homeless at {M7http://www.courierwebcasts.com/play.php?vid_id=419&file=thornton.flv