CHICAGO – Bill Muir was burning out as an operations manager for a beverage company and started looking for another career. When his brother-in-law used a handgun to kill himself, Muir decided to clean up his sister's place.

Her gratitude for his gesture of grit and kindness gave him an idea. Five months later, Muir became a crime-scene cleaner.

"I wanted to start helping people," he said one recent afternoon before fielding a call to clean up a homicide scene. "And seeing my sister's face after … I knew this is how I can help."

In starting Bio-One Chicago last year, Muir and his wife, Dawn, joined the ranks of a profession that blends the demeanors of a funeral home director and grief counselor with a construction contractor who has a strong stomach and intimate knowledge of biohazard disposal. It is also a largely unregulated profession experiencing steady growth, fueled by increasing fear of contamination and disease, and awareness that the services exist, experts say.

"It's a hard thing to do," said Dr. Richard A. Jorgensen, coroner for the Chicago-area county of DuPage, who uses Aftermath Services LLC, an area firm, to clean the county morgue. "It's something that's little-understood."

Bio-One, Aftermath and other local companies are called to homicides, suicides, unattended deaths and the homes of hoarders. Sometimes they are called to clear a meth lab.

"When people ask me what I do, they say, 'wow,' and then they get really interested," said Dan Reynolds, a lieutenant in a fire department in suburban Chicago who started Chicago Crime Scene Cleanup in 2007 with his wife, Kelly, to supplement his income. "But I don't think they understand what all goes into it. They don't understand the emotional side of it."

Potential clients are enduring the worst time of their lives, cleaners say.

"Nobody calls me on a good day," Reynolds said. "Trying to understand what they're going through is a big part of it."

When a cleaner arrives on a site, bodies are gone but the dreadful signs of what happened remain, including body fluids and matter on floors, walls and ceilings. Insects, rodents, feces and overwhelming odor also can be present.

Reynolds recalled a job several years ago, when he was called to a murder scene in a third-floor apartment on Chicago's South Side. The victim had been dead for several days, during which time the sink overflowed, flooding the third-floor unit and apartments below it.

"We were out there for a couple weeks," Reynolds said.

Muir handled a recent, notorious crime scene: the murders of six family members in a brick bungalow in Chicago's Gage Park neighborhood on Feb. 2. Five employees worked for 12 hours to restore the home, Muir said.

At a church service for the victims, Diego Uribe, a relative, hugged Muir and praised him for cleaning the home, Muir recalled. About three months later, Uribe and his girlfriend were charged with the killings.

"I was dumbfounded," Muir said.

Graphic scenes can crowd the minds of cleaners, Reynolds and Muir said. "You have to be really good at removing yourself from the situation," said Reynolds, 42. "Once you put it in terms that you're there to do a job and help the family, it becomes a little easier."