In the parking lot of a Salisbury bar, Corinne Ray considered her next move. It was happy hour. Ray had identified the automobile she was looking for, belonging to a wife suspected of infidelity, but the woman was not inside the building.
As the private investigator sat in her car, the woman in question rolled up on the back of a motorcycle. The woman and her paramour started kissing, and Ray reached for her camera.
The couple seemed ''to have had a few" drinks and too caught up in the moment to care about the apparent soccer mom taking photographs, Ray recalled.
''They kind of looked over at me, but they were focused on what they were doing," she said.
She got her evidence but was reluctant to leave. She was concerned about the wife, who appeared to be in no condition to drive. So Ray parked in the lot next door, ''thinking about what to do next," and didn't notice that the man on the motorcycle had pulled up to her car.
''What are you doing, taking pictures of us?" he asked. ''Was that you over there?"
He was a big guy.
''Your bike is really cool," Ray said, smiling and holding her can of mace discreetly at her side, hoping it wouldn't be needed. ''I was looking at motorcycles for my husband."
Perplexed and possibly flattered, the man rode off.
In this job, you need the ability to think on your feet.
Sophisticated technology, updated surveillance techniques, and new areas of law have changed some parts of the job description, but local private investigators say the profession carries many of the requirements it always has. Along with intellect and fearlessness, a PI needs an inquisitive nature balanced by an instinct for self-preservation.
''I've gone into some really bad areas, to find witnesses for lawyers and locate missing persons," said Ray, 44, who runs Beverly-based North Shore Investigations Inc. The company specializes in missing persons cases, background checks, and witness interviews for civil cases.
''I try to look nonthreatening, which I am, and I think that's an advantage for me," she said.
John Nardizzi, whose work as head of Boston-based Nardizzi & Associates Inc. often takes him to the North Shore, said it's important to be able to defuse situations when a subject is nervous, angry, or doesn't want to talk -- as when he worked on a racketeering case involving young, low-ranking organized crime associates.
''I always try to keep in mind," Nardizzi said, that even if his subjects are threatening him, ''the reason is, they're nervous and upset. I just try to bring it down. The vast majority of the time, I need to rely on my skills and keep the person calm."
Doug Vigliotta, who runs Elite Detective Services Inc. in Beverly, recalls being threatened with guns, knives, and a hammer. He has been run off the road, and threatened with death if he showed up to testify in a civil case. (He did anyway.)
Curiously, he has been threatened or assaulted more often on workmen's compensation cases than others that might be considered more serious, such as criminal cases, he said. One time he was spotted while tailing someone on the way to an under-the-table job, and the suspect pulled a U-turn on Route 1 and came driving at his car.
Other times, he was simply doing surveillance in the wrong neighborhood at the wrong time.
''They might be doing something else, and may think I'm after them," said Vigliotta, 42, who specializes in surveillance, locating individuals, and insurance fraud.
Nardizzi, 39, specializes in civil and criminal trials and business fraud, and performs background checks.
He has also done investigations in wrongful conviction cases, an area of law that has been ignited in recent years by advances in DNA research. Among his clients is Dennis Maher, whose conviction in a Lowell multiple rape case was overturned in 2003 when DNA tests proved he was not the perpetrator.
In a case like that, a private investigator may be asked to find and reinterview witnesses, which can be difficult when years have passed since the original charges. The witnesses may also be law enforcement officials who do not want to cooperate, particularly if there is a claim that errors were made in the investigation, or worse.
''Some have been very cooperative, but when it comes to talking with those that have made mistakes, they want no part of cooperation and do everything they can to thwart our investigation," Nardizzi said. ''But some guys really have come forward."
In one case, Nardizzi found that a witness he hoped would provide key evidence had died.
''That's common," he said. ''These are 20-year-old cases."
Hiring a private eye isn't cheap. Ray charges $50 an hour, Vigliotta's fee runs from $50 to $125, depending on the case, and Nardizzi charges $152 per hour.
Vigliotta is a former probation officer and criminal justice major, Ray a former journalist, and Nardizzi a lawyer -- three professions common for those going into the field.
Private investigators are a discreet bunch, and not just with those they're investigating. When asked for details about their occupations, the PIs all held back bits of information, for various reasons, including their own safety. They screen their clients carefully, curious about the motives of some who try to hire them.
In cases where a client wants the investigator to find a missing person, the missing person may simply not want to be found.
''There are a lot of cases I won't take," said Ray, who has been asked to bug houses and wiretap telephones, which is illegal.
Nardizzi recounted the time a California woman called him for help with a blackmailing boyfriend, who claimed to be a Mafia associate with a powerful and dangerous godfather named Nick Pacini from Revere.
Turns out, there was no Nick Pacini.
Nardizzi said the guy ran a scam in which he would work himself into social circles, pass himself off as connected to the mob, and then borrow or extort money from people who were frightened of his associations.
One afternoon, he brought a bunch of people to eat at an Italian restaurant. He talked about life in ''the old country" (the guy turned out to be Egyptian, Nardizzi said), ordered heavily, and when the very large bill came, he told his guests, ''No, no, no. . . . This place is part of the family. We're into these people. No problem."
In fact, Nardizzi said, he had set up his marks by going into the restaurant a few hours earlier and prepaying the bill.
The man was later indicted for his scams, and among the articles in his possession was a Massachusetts driver's license bearing the name ''Nicolai Pacini."
''It was a picture of him, with a wig on, and a hat," Nardizzi said.