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 murder 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 murder into the depths of the Boston underworld and its cozy 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.

On May 27, 1981, kids 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 a round of golf.

Changed outlook

Huff was 25 and undaunted when his supervisor told him the investigation into that afternoon's murder likely would change everything he'd thought about police work.

"Damn, I wish I hadn't been on duty that day," Huff would later say, after the case had consumed his life.

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.

Huff interrupted vacations to chase leads. He called Wheeler's son, David, sometimes in the early morning hours. His dedication gave Wheeler's family hope that someone would eventually be brought to justice.

"He defines the word 'relentless,"' David Wheeler said.

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.

When the 78-year-old Rico opened the door in his undershorts Oct. 9, Huff found the moment bittersweet.

"What I was really thinking," he said, "was 'Can I get past this and reclaim some normalcy?'"

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

No trial date has been set in Oklahoma.

"It always comes down to the last man standing," said David Wheeler. "Rest assured, Mike Huff will always be the last man standing."