Bryan Zirbes, Eric Lindeman and Kenneth Rodeski worked in the tree trimming business. Each had lived in the same small town in central Minnesota, Little Falls. Each came to southwestern Pennsylvania for work, one after another, taking a job with the same company.

And one by one, in two years' time, each died in Allegheny County.

"Just statistically, that's an aberration," said medical examiner Karl Williams. It's unusual to see three unnatural deaths "that fall under my jurisdiction from one small town that is not in Allegheny County, all working for the same company."

Zirbes died of an accidental overdose of cocaine and painkillers in 2010. Lindeman hanged himself in August. Rodeski was found dead in a bathtub last month, another possible overdose that police are investigating.

"While they're suspicious by nature, none have any indication that there was a criminal act committed to those victims beyond the illegal narcotics," said Lt. Andrew Schurman of the county police homicide unit.

But the investigation surrounding the deaths will remain open, he said.

"It's definitely unusual. We don't see that very often."

All three worked for Nature Boyz Tree and Landscape Service, a Little Falls, Minn., business that advertises a specialty in working on large and dangerous trees. It is owned by 34-year-old Lee Liebel of Little Falls, according to court records, and has a branch in Allegheny County registered at 6 Landings Drive -- the Days Inn in Harmarville.

Mr. Liebel could not be reached for comment. His cell phone -- also the number listed for Nature Boyz -- is not accepting calls, and he did not return email and Facebook messages. County homicide detectives have interviewed him, documenting his relationship with his employees. No charges have been filed in connection with their deaths.

Little Falls has seen its share of tragedy lately. The town of 8,000 residents, about 90 minutes northwest of Minneapolis, made national news after police said a 64-year-old man shot two teenagers to death during an apparent break-in at his home on Thanksgiving Day.

Though she knows the tree-workers' families, Little Falls Mayor Catherine VanRisseghem said she was not aware that Kenneth Rodeski's death marked the third of a Little Falls resident in Allegheny County.

Like many small towns, Little Falls has been hit hard by the recession. Compared with other cities in Minnesota, unemployment there is "quite high," the mayor said. The boating industry -- once booming in the Mississippi River town -- provides only 275 jobs now, down from 1,000 in years past, she said.

Many in the tree-trimming business are drawn out of state when work is thin, especially during Minnesota's brutal winters. Zirbes and crews he worked with followed storms around the country. Rodeski had worked in Colorado. Lindeman made good money climbing in Chicago.

"In the winter months, the tree-trimming service comes to a standstill," Mayor VanRisseghem said.

Barbara Liebel said her son, Lee, started moving around the country for work more than 10 years ago, going wherever there was a disaster that would promise steady cleanup work. He set up shop in Texas, North Carolina and, around 2010, the Pittsburgh area.

On Nov. 14, Springdale Borough police were called to an upstairs apartment at 1037 Keene St., where Mr. Liebel and some of his employees lived.

Officers found Rodeski, 48, dead in the bathtub. Sgt. Mark Thom said Mr. Liebel told police that he had placed Rodeski in the tub and turned the shower on to wake him. He then called 911, telling dispatchers that Rodeski had "OD'ed on alcohol," Sgt. Thom said.

Lt. Schurman said there were no signs of violence. No tenants are permitted in that apartment while the county investigates, Sgt. Thom said.

Rodeski, a climber, owned his own business, Ken Tree's Service, but had made a few trips to Pittsburgh for seasonal work with Mr. Liebel's company, his sister Mary Rodeski said. He was also friends with Mr. Liebel's parents, who paid for his plane ticket to Pittsburgh Nov. 12, according to both Barbara Liebel and Ms. Rodeski.

Rodeski had struggled with drinking and money problems since his divorce, Ms. Rodeski said, adding that her brother told her that on this trip, he was coming to collect $10,000 Mr. Liebel owed him.

"Ken always saw the best in everybody," she said. "He would do anything for you."

On Aug. 27, three months before Rodeski's death, Tarentum police found 29-year-old Eric Lindeman hanging in the bathroom of an apartment he shared with his girlfriend. The medical examiner's office ruled the death a suicide.

Police discovered Lindeman hours before he was scheduled to appear for a preliminary hearing on assault charges, stemming from a March incident in which he was accused of stabbing Mr. Liebel in the face with a box cutter.

Lindeman's girlfriend, Brittany Bargerstock, 28, left for about 90 minutes that night to feed her brother's dogs while Lindeman stayed at their apartment.

"He found his window where I wouldn't be there for a little bit, and he took it," she said. "I've thought of every scenario under the sun, and I think he did it himself."

Lindeman was a gifted climber working in the Midwest when word of his skills made its way to Mr. Liebel, who persuaded him to move here with the promise of more money. The man friends called "Super Climber" arrived in Pittsburgh in 2010 to work for Nature Boyz -- even though he could pull in $5,000 a week trimming in Chicago, Ms. Bargerstock said.

"He was obsessed with climbing trees," Ms. Bargerstock said.

At first, Ms. Bargerstock said, it was good: Bonuses, shopping trips, benders at the bar, including one in Springdale where she works and would first meet Lindeman, whom she dated for nine months, and the others.

In March, Lindeman was arrested in Springdale for stabbing Mr. Liebel during a dispute about wages. He hanged himself the evening before he was to appear in court in that case.

Though Mr. Liebel was not allowed to contact Lindeman after the March stabbing, Ms. Bargerstock said, he would ask her to facilitate work assignments for Lindeman. A final Aug. 8 text message from Mr. Liebel to Ms. Bargerstock reads: "Can Eric climb today?"

Sometime in early August, Lindeman started working for Emery Tree Service in Tarentum, a supervisor at that company confirmed. Lindeman's mother, Peggy Kloeckl, said that before his death, Lindeman had submitted child support paperwork for his 6-year-old son in South Dakota.

The same year Lindeman arrived, 49-year-old Bryan Zirbes also was drawn to Pittsburgh to work as a salesman for Mr. Liebel's business.

"He was excited because it was change of pace," his friend Brian Lindberg said.

Zirbes had lived with the Lindberg family in Little Falls for a few months during a transitional period in his life. Mr. Lindberg was aware that Zirbes had previous drug problems, but said he was clean while he lived there. He came to Pittsburgh around May 2010.

After a couple of weeks here, he called home, said things weren't working out with his boss and he wanted to come back to Minnesota, Mr. Lindberg said.

He was found dead by Kennedy police a few weeks later, June 29, inside a motel room surrounded by seven ferrets, a German shepherd and a caged scorpion.

"I distinctly remember this call because there was a roomful of animals," said police Chief Anthony Bruni, who responded to the scene.

At that time, employees of Nature Boyz lived at the motel, including Mr. Liebel, who called police after finding Zirbes unresponsive, Chief Bruni said. At some point after units arrived, Mr. Liebel left the room, and police later woke him up in his hotel room. Though it was "a very unusual situation," Chief Bruni said he didn't see any evidence of a crime. "I didn't believe there was anything suspicious about it at all," he said.

The medical examiner's office determined Zirbes died from an accidental combined overdose of cocaine, oxymorphone and ethanol (ethyl alcohol).

Police had his address listed as St. Cloud, Minn. -- about 30 minutes from Little Falls -- but the Lindbergs said he lived in Little Falls most his life.

Nature Boyz Tree and Landscape Service received an "F" rating from the Minnesota Better Business Bureau for failure to respond to two complaints filed against the business. The bureau made two or more requests for background information from the business, which is not accredited through the bureau, though businesses are under no obligation to seek that accreditation.

In 2011, the company was sued in Allegheny County for cutting a client's trees with contaminated equipment in a month when trees would be susceptible to a disease. When the trees contracted the disease, the couple were forced to remove them and sued for $25,000, according to court documents. Mr. Liebel was in judgment of default for failing to take action in the case, those records show.

Mr. Liebel's mother asserts her son took care of his employees and gave them jobs. Their missteps, she said, were a result of problems that they carried with them here.

"I think it's just a coincidence," she said of their deaths.

She also said that Lee Liebel's father, Kim, was en route to Pittsburgh to pack their son's equipment and move him back to Little Falls to dissolve the company.

"He's getting out of the tree trimming business," she said.

First Published: December 9, 2012, 10:15 a.m.