When Joe Maruca decided to vie for the top spot at the West Barnstable Fire Department in 2005, his 11 years there as a volunteer captain didn’t save him from scrutiny.

The town hired David Nadolski of Orleans, a former G-man turned private detective, to pry into the lives of Maruca and everyone else who applied for the chief’s position.

Nadolski spared nothing. He verified educational backgrounds and personnel records. He checked medical records, if necessary. He interviewed, usually in person, references, current and former employers, and co-workers, spouses and ex-spouses.

“At the time, I hated it,” Maruca said. “I just felt it was terribly intrusive. And it made you feel as if they were almost looking to find something wrong with you, which of course they are. Being on the receiving end of a good background check doesn’t feel good, even when you know there’s nothing out there.”

“They’re thorough,” Maruca said. “Don’t ask me how they do it, but they seem to be able to find information very well.”

That’s exactly what municipalities like Barnstable are banking on. More and more, governments are turning to private investigators for background checks, fraud investigations and other sleuthing.

“The biggest trend right now is private investigators getting hired by government agencies,” said Jimmie Mesis, editor in chief of PI Magazine, the national trade publication for professional investigators.

In the past few years, municipal governments have started hiring more PIs for background checks and residency verifications. School boards are hiring gumshoes to make sure their students actually live in the towns in which they attend school. Colleges do the same, since in-state students get tuition discounts, Mesis said.

An influx of government work isn’t the only aspect of PI work that has evolved over the years. “Now they’re more likely to carry a wireless laptop than they are to carry a gun, more likely to be expert researchers as compared to knocking on doors,” Mesis said.

And the number of women entering the field is “skyrocketing,” he said.

In larger cities, bountiful client loads allow detectives to specialize in particular areas — sophisticated financial investigations, for instance.

But on the Cape, being picky doesn’t pay.

“Being a PI on the Cape is tough,” said Nadolski, who was snapped up by one of his corporate clients in 2006. “The business is kind of sporadic. You can’t be choosy if you’re planning to make money at it and cover your expenses and be able to support yourself. You definitely have to be a generalist to survive.”

And while snooping on cheating spouses is sometimes still part of the job, the bulk of detective work — detective work that pays anyway — is in insurance fraud investigations, primarily for workers-compensation claims, private eyes said.

Bloodhounds might also work for companies by reconnoitering on competitors’ tactics or former employees suspected of stealing clients. They work for private citizens and lawyers alike on civil court cases. And they often work for defense attorneys on criminal cases, interviewing witnesses to mount the defense to which every suspect is entitled.

An uneasy relationship

That doesn’t mean work in the field always goes smoothly. Take, for instance, Andrew Sandelin, a licensed, self-employed private investigator for the past 10 years from Boston. Last summer, Sandelin was in the employ of defense attorneys preparing a case for two Cape men charged with drug and gun offenses.

Sandelin went to a Barnstable home to interview a witness, a standard practice. But the woman called police.

Barnstable police Officer John Campbell came to the scene, checked Sandelin’s paperwork, including his gun license, and spoke to the witness. He then called Barnstable Detective Brian Guiney, who had investigated the case for police. He, in turn, arrived and also asked Sandelin who he was and why he was there, Sandelin testified in Barnstable Superior Court.

“[Campbell] said I was not to come to this town without checking in” with the police department, Sandelin testified. He was intimidated enough that he stopped trying to question particular witnesses in the case.

Checking in was something he’s never been told to do before, he said, and with good reason. Experts said no such laws mandate PIs checking in with police departments, whether they’re in the field to interview witnesses or perform surveillance.

Barnstable police do request that PIs check in for surveillance work, though it’s not mandatory.

“Sooner or later, someone’s going to call,” said Barnstable Police Chief Paul MacDonald, adding that police can unintentionally ruin a private investigator’s stakeout without prior notice.

The voluntary check-ins have been in place for years without any problems, MacDonald said.

“If there’s one area where PIs encounter opposition and resistance in the field it’s from police in uniform who come upon a private investigator performing surveillance,” said Thomas Shamshak Sr., a former police chief for two Massachusetts towns and now a private detective.

Many investigators do give police a courtesy heads-up. Shamshak, a past president of the Licensed Private Detectives Association of Massachusetts, helped draft a form detailing a PI’s name, make and model of car, and what area he’ll be working in — though not the identity of who he’s watching.

That sheet can be faxed to police departments voluntarily, and a clipboard full of the forms at the Barnstable Police Department is why Campbell thought Sandelin was supposed to check in, Campbell testified.

“If somebody calls in a suspicious vehicle, [police] are able to be proactive. They can say, ‘We know who that is,’” explained Shamshak, who worked with defense attorney Kevin Reddington on the case of now-convicted Nantucket murderer Thomas Toolan III, among other high profile cases.

Some private detectives don’t like to tell police what they’re up to — often it depends on how much stealth they need for any particular case.

“The rule that I have always applied is that I never check in with the police department. If I do a good job, I blow in like the wind and I blow out. Nobody ever knows I was there,” said Mesis, of PI Magazine. “Cops don’t like PIs. And then when they retire, they become a PI.”

Mesis didn’t come from law enforcement, but half of all private investigators do, he said.

Getting to crack cold cases could be one draw for former cops. Twenty-five years after the 1980 murder of Frances Carriere, private investigator and former Sandwich cop Terrance O’Connell, who’s also a defense attorney, helped find her killer. He and state police investigators Chris Mason and Paul White tracked down Stephen Stewart, the man who stabbed Carriere in a murder-for-hire scheme. Stewart was convicted in 2005.

“My angle has always been the same,” O’Connell said. “Just look for the truth.”

Dull and dangerous

But as grand as it sounds, some PI work can be dull — and dangerous. “It’s very taxing. You’re sitting watching a house for eight or 10 hours,” said longtime PI Robert Simmons, of Simmons Agency in Hyannis and Boston. Listening to the radio or books on tape is fine, but there’s no reading, lest the PI miss his mark.

“It’s boring. It’s boring as all heck,” Simmons said. “It takes a certain type of person to do a long stakeout.”

Working in the field can be scary, too. “I’ve had guys come at me with guns. I’ve had guys break bottles and say they’re gonna mess up my face,” Simmons said.

He’s even had to be careful of his own clients. One client admitted he wanted to find his father, who had abandoned him as a child, because he wanted to kill him. Simmons has turned down other clients whose stories he just doesn’t believe.

For insurance work, Simmons charges companies about $100 to $125 an hour, and he pays PIs who work as vendors for him up to $50 an hour. The average insurance fraud case takes 16 hours of work, he said. Despite the danger, boredom, and hard work, Simmons said he’s had plenty of fun, too.

The only real requirement to be a private detective is a special license issued by the Massachusetts State Police. Without that, you’re just a stalker.

A PI’s diligence can garner respect. Now that he’s West Barnstable fire chief, Maruca appreciates the efforts of Nadolski, formerly with the Federal Bureau of Investigation. Maruca is also a part-time estate attorney and has conducted his own background checks of would-be firefighters.

“We need the right people, or our system doesn’t work,” Maruca said of his fire department. “The community has to trust us. We have complete, unfettered access, for the most part, to everybody’s home and business in this community.”

If Nadolski were still in the business — and if the department had the funds — Maruca would have hired him.

“After I became chief and [Nadolski] checked me out, I have recommended them to a number of clients.”