GERALD, Missouri - July 1, 2008 - Like so many rural communities in the country’s middle, this small town had wrestled for years with the woes of methamphetamine. Then, several months ago, a federal agent showed up.

Arrests began. Houses were ransacked. People, in handcuffs on their front lawns, named names. To some, like Mayor Otis Schulte, who considers the county around Gerald, population 1,171, “a meth capital of the United States,” the drug scourge seemed to be fading at last.

Those whose homes were searched, though, grumbled about a peculiar change in what they understood - mainly from television - to be the law.

They said the agent, a man some had come to know as “Sergeant Bill,” boasted that he did not need search warrants to enter their homes because he worked for the federal government.

But after a reporter for the local weekly newspaper made a few calls about that claim, Gerald’s antidrug campaign abruptly fell apart after less than five months. Sergeant Bill, it turned out, was no federal agent, but Bill A. Jakob, an unemployed former trucking company owner, a former security guard, a former wedding minister and a former small-town cop from 23 miles down the road.

Mr. Jakob, 36, is now the subject of a criminal investigation by federal authorities, and he is likely to face charges related to impersonating a law enforcement officer, his lawyer said.

The strange adventures of Sergeant Bill have led to the firing of three of the town’s five police officers, left the outcome of a string of drug arrests in doubt, prompted multimillion-dollar federal civil rights lawsuits by at least 17 plaintiffs and stirred up a political battle, including a petition seeking the impeachment of Mr. Schulte, over who is to blame for the mess.

And the questions keep coming. How did Mr. Jakob wander into town and apparently leave the mayor, the aldermen and pretty much everyone else he met thinking that he was a federal agent delivered from Washington to help barrel into peoples’ homes and clean up Gerald’s drug problem? And why would anyone - receiving no pay and with no known connection to little Gerald, 70 miles from St. Louis and not even a county seat - want to carry off such a time-consuming ruse in the first place?

Mr. Jakob’s lawyer, Joel Schwartz, said that what happened in Gerald was never a sinister plot, but a chain of events rooted in “errors in judgment.” Mr. Schwartz said he believed that at least three Gerald police officers, including the chief, knew that Mr. Jakob was not a federal drug agent or even a certified police officer.

“It was an innocent evolution, where he helped with one minor thing, then one more on top of that, and all of the sudden, everyone thought he was a federal agent,” Mr. Schwartz said. “I’m not saying this was legal or lawful. But look, they were very, very effective while he was present. I don’t think Gerald is having the drug problem they were having. I’ve heard from some residents who were thrilled that he was there.”

There were numerous arrests during Mr. Jakob’s time in Gerald (the exact number is uncertain, local law enforcement officials said, as legal action surrounding the case proceeds), but Mayor Schulte said that Mr. Jakob had, in fact, gone to elaborate lengths to deceive local authorities, including Ryan McCrary, then the police chief, into believing that he was a federal agent - with the Drug Enforcement Administration, the Marshals Service or some other agency.

In addition to having a badge and a car that seemed to scream law enforcement, Mr. Jakob offered federal drug enforcement help, Mr. Schulte said. (Local officials thought the offer must have somehow grown out of their recent application for a federal grant for radio equipment.) Mr. Jakob even asked Chief McCrary to call what he said was his supervisor’s telephone number to confirm Gerald’s need for his help, the mayor said.

When the call was placed, a woman - whose identity is unknown - answered with the words “multijurisdictional task force,” and said that the city’s request for federal services was under review, the mayor said. Mr. Schulte said he now suspects that Mr. Jakob adapted the nonexistent task force name from the “Beverly Hills Cop” movies starring Eddie Murphy.

“Not only were these officers taken in, but so was everybody else,” said Chet Pleban, a lawyer for Mr. McCrary and the other two members of the police force who lost their jobs after Mr. Jakob’s real identity came to light.

Of the firings, Mayor Schulte said, “Nobody wanted to, but the city’s lawyer recommended it.”

When residents first began noticing Mr. Jakob, he certainly looked the part. His hair was chopped short, residents recalled, and his stocky chest filled a black T-shirt he sometimes wore that read “Police.” They said he wore military-style boots, pants with pockets running down the legs and carried a badge (his lawyer said it was from a former job as a security guard in St. Louis). And his off-white Ford Crown Victoria was decked out with police radios and internal flashing lights, residents said.

He first came to town in January, his lawyer said, to meet Chief McCrary, whose experiences serving in Afghanistan Mr. Jakob had read about in a local newspaper. Mr. Jakob was considering contract work overseas, Mr. Schwartz said, and the pair hit it off.

Soon, the arrests began. Some of those whose homes were searched said they had been kicked in the head and had shotguns held against them. Mr. Jakob, many said, seemed to be leading the crew of Gerald police officers.

“He was definitely in charge - it was all him,” said Mike Withington, 49, a concrete finisher, who said Mr. Jakob pounded on his door in May, waking him up and yanking him, in handcuffs, out onto his front yard.

Mr. Withington said he had not yet been charged with a crime; Gary Toelke, the Franklin County sheriff, confirmed that no local charges had been issued against him. But the mortification of that day, Mr. Withington said, has kept him largely indoors and led him to consider moving. Since the search, residents have tossed garbage and crumpled boxes of Sudafed (which has an ingredient that can be used to make methamphetamine) on his lawn, he said, and he no longer shops in town, instead driving miles to neighboring towns.

“Everybody is staring at me,” he said. “People assume you’re guilty when things like this happen.”

When Linda Trest, 51, a reporter at The Gasconade County Republican, started hearing complaints from people whose homes had been searched, she began making inquiries about Mr. Jakob.

“Once I got his name, I hit the computer and within an hour I had all the dirt on this guy,” Ms. Trest said.

As it turned out, Mr. Jakob, who is married and lives near Washington, a small town not far from Gerald, filed for bankruptcy protection in 2003 when he owned a trucking company, and had, at 22, pleaded guilty in Illinois to a misdemeanor charge of criminal sex abuse of someone in her teens.

Since the 1990s, he had worked, at times, as a police officer in tiny departments in towns like Kinloch, Mo., and Brooklyn, Ill., though he never seemed to stay anywhere long and was never certified as a police officer in either Missouri or Illinois, his lawyer said. (Under some conditions, short-term employees with some departments are not immediately required to have state certification.)

As in Gerald, he impressed some, if only at first. “He seemed to have experience on the street,” said J. D. Roth, the police chief in Caseyville, Ill., where Mr. Jakob was a temporary part-time officer for almost two months in 2000. “He walked the walk and talked the talk.”

In Gerald, just a day before it was revealed that he was not a federal agent, the city aldermen voted to make Mr. Jakob a reserve officer; he wanted the designation, Mr. Schulte said, so he could enforce local ordinances, and he stood before the aldermen, hands behind his back, seeking the title.

Mr. Jakob offered city officials three contact numbers - his personal cellphone, a cell phone he said he used for drug informants and his “multijurisdictional task force” cell phone, Mr. Schulte said.

“It was the movie, ‘Catch Me if You Can’ all over again,” said Mr. Schulte, referring to the 2002 film starring Leonardo DiCaprio as a master of deception. “I’m telling you, with this guy, everything was right.”