TULSA, OKLA. ? The sun had yet to rise over Miami Shores, Fla., but the Oklahoma lawman at H. Paul Rico’s front door wasn’t waiting any longer. After 22 years, it felt good to interrupt the retired FBI agent’s sleep with a knock.

“I’m Sgt. Mike Huff,” the detective told Rico before informing him he was under arrest for the 1981 slaying of a Tulsa businessman.

After decades of pursuit, neither one needed the introduction.

Huff’s mustache had gone salt-and-pepper since he was first assigned the case , and his marriage had buckled under the strain. But the tangle of false leads, wrecked vacations and outside efforts to thwart him had finally come undone that day in early October.

If it hadn’t been him, Huff says, some other Tulsa police detective would have trailed Roger Wheeler’s homicide into the depths of the Boston underworld and its relationship with the FBI.

Huff’s tenacity, however, has stood out, even as mobsters and corruption stood in the way.

“Mike was a bulldog,” said Robert Fitzpatrick, a former assistant chief of the FBI’s Boston bureau. “He never let this go.”

Tulsa Police Chief Dave Been believes Huff and the threat of Oklahoma’s death row helped break mob kingpin Stephen “The Rifleman” Flemmi, who pleaded guilty last week in 10 murders, including that of Wheeler.

“Sgt. Huff just kept the pressure and kept the pressure,” Been said. “I think that’s what made Flemmi roll over.”

Spared the possibility of lethal injection, Flemmi is cooperating with investigators and has told them Rico and others wanted Wheeler killed. A confessed triggerman said Rico, who denies any involvement in Wheeler’s death, aided the hit by providing information about Wheeler.

Tulsa Police Sgt. Mike Huff investigates the shooting of Roger Wheeler at Southern Hills Country Club in this May 27, 1981, file photo. It took Huff more than two decades to uncover the plot behind Wheeler's death.

On May 27, 1981, children in the pool at a Tulsa country club heard the shot from the parking lot. Wheeler, the 55-year-old chairman of Telex Corp. and owner of Miami, Fla.-based World Jai Alai, had been shot in the head after playing golf.

The investigation Huff led went cold at the start. Investigators eventually focused on Wheeler’s suspicions that money was being skimmed from World Jai Alai. Rico, who retired from the FBI in 1975, was the company’s chief of security.

In 1982, a member of Boston’s Winter Hill Gang was gunned down after reportedly telling the FBI that he’d rejected an offer to kill Wheeler. Another person of interest to Huff, World Jai Alai executive John Callahan, was found dead in the trunk of a car.

Trouble with FBI

“We were chasing leads all over the place,” Huff said. “We very naively thought that as far as the Jai Alai angle, the FBI would bring us into the loop.”

A year after Wheeler’s murder, though, Huff’s naÃivete was wearing off. He began to suspect Rico, who had cultivated Flemmi as an informant in 1965.

As the investigation went on, federal agents accused Huff of jumping to conclusions, he said. Tulsa detectives were led on wild goose chases when Boston FBI reports validated false leads, Huff later learned.

Former Boston FBI Agent John Connolly was convicted last year of protecting gangster informants, including James “Whitey” Bulger, a fugitive since being tipped off to his pending indictment in 1995.

Five years later, Huff named Flemmi, Bulger, confessed triggerman John Martorano and Rico in an affidavit in Tulsa County. Dist. Atty. Tim Harris brought murder charges against all but Rico, wanting more evidence to take to court.

Perseverance pays

Meanwhile, Huff led a homicide division in making arrests in more than 90 percent of Tulsa murder cases, a figure that compares with 62 percent nationwide.

Still, the stress of the unsolved Wheeler case wrapped tighter around him, and Huff’s marriage fell apart. So when the 78-year-old Rico opened the door in his undershorts Oct. 9, Huff found the moment bittersweet.

Even with Flemmi’s plea and Rico’s arrest on a charge of first-degree murder, the Wheeler murder investigation isn’t over. Bulger remains at large, and the detective says without elaborating that Flemmi’s confession “has opened a can of worms.”

Rico, meanwhile, is being held in Florida and faces an extradition hearing Tuesday.