They usually spend their time analyzing drug dealers' cell phones or child traffickers' laptops for evidence, but Chicago FBI forensic experts recently lent their expertise to an altogether different kind of caper: finding the puck scored by the Blackhawks' Patrick Kane to win the 2010 Stanley Cup.

The puck has been missing since Kane slipped it into the back of the net during overtime of Game 6, ousting the Philadelphia Flyers. The goal happened so fast that few even realized he scored. Kane skated to the opposite end of the ice and into the arms of his teammates. They celebrated. The Flyers mourned on the bench.

And someone picked up the puck and made good their escape.

The Blackhawks don't know where it is. Nor does Kane. Or the Flyers for that matter. Philadelphia's notorious puck-lifter, Chris Pronger, is on record as denying he has it. Curators from the Hockey Hall of Fame in Canada couldn't find it that June night when they tried to round up memorabilia.

While the missing puck has been the topic of a few news blurbs here and in Philadelphia, the search for it got a serious boost when the Chicago FBI office in recent weeks stepped in to help a local businessman who is offering a hefty reward for the approximately six precious ounces of rubber.

It is certainly not the first time a key piece of hockey history has disappeared in the bedlam of a celebration. Just about a year ago, Sidney Crosby lost track of his stick, gloves and the puck after scoring the winning goal in Team Canada's victory over the U.S. in the Olympics.

But the quest for Kane's game-winning puck might be the first time the federal government has offered an assist — however informal.

"All we're doing is helping," Chicago FBI spokesman Ross Rice said. "The people who are doing this are doing it on their own time. They feel they are a part of history."

The FBI "probe" got started after local restaurateur Grant DePorter, CEO of Harry Caray's, offered a $50,000 reward for the puck.

DePorter is designing the Navy Pier Harry Caray's location with a hockey theme — Kane and Hawks great Bobby Hull are partners — and he asked around last summer about the winning puck.

"It sounded like no one knew (what happened to it),'' DePorter said. "It was a mystery."

Soon after, DePorter put out the bounty on the puck, expecting that a Flyers fan had it and would willingly part with the "painful memory'' for the cash.

A man called with good news in late July, DePorter said. He was at the game, sitting close to the ramp, and had been handed the puck by someone with access to the ice, he said. He sent it to DePorter in July.

At that point, DePorter realized he had a problem — how could he possibly know for certain if it was the puck?

DePorter, who had taken a class offered by the FBI on its investigative techniques, was familiar with the whiz-bang tools that the agency uses every day to catch criminals. He called Rice for some help.

Armed with footage from NBC of the winning goal, the FBI took on the task.

The FBI determined that a single puck was used the entire 4:06 of overtime. But unfortunately — for the purposes of this investigation anyway — the NBC cameras had panned away after the score to focus on Kane as he streaked to the other end of the ice.

"The last image of the puck was it was in the back of the net and a referee can be seen skating into the camera shot," Rice said.

But that was hardly enough to lead to a suspect.

So the forensic examiners turned to the more immediate question — was the turned-in puck the Stanley Cup winner?

Again, they studied the high-definition NBC footage to isolate nicks and marks on the puck used in overtime.

"Hockey is a very fast game and to freeze a frame and get a usable image takes specialized equipment that we have," Rice said.

But after examining photos of the puck handed over to DePorter, it was clear — no match, the FBI concluded.

DePorter has not given up. The reward still stands and should another puck surface, the FBI is ready to help again.

With their Microviper MV2 portable video microscope, the examiners believe they will be able to compare each nick on any puck that is turned in to the digitally-enhanced images they have of the winning goal.

The microscope is more typically used in crimes such as break-ins, where burglar tools can be matched to distinctive marks left on busted doorjambs, Rice said. The same concept applies to the photo and the puck.

"We feel we have enough in terms of visual evidence to include or exclude any future pucks,'' Rice said.

There is, of course, the possibility that more evidence will surface, perhaps more footage.

Asked if security cameras might have caught the culprit, Flyers spokesman Ike Richman said Friday he didn't know.

"No one has asked us to (check)," he said.

Investigators — and Hawks' fans — can take heart that hockey and Olympic authorities figured out what happened to Crosby's equipment and winning puck. His gloves inadvertently ended up in a teammate's equipment bag; his stick was being shipped to Russia; and a review of footage revealed that an official picked up the game-winning puck.

asweeney@tribune.com