Winnipeg businessman Marty Halprin with the 10-speed bike he prevented from being stolen last week. He's looking for the bike's rightful owner. (CBC)

A Winnipeg business owner is hunting for the owner of a bicycle that he stopped from being stolen in the city's downtown late last week.

On Friday, Marty Halprin was passing by the corner of York Avenue and Smith Street when he spotted a man furiously rocking a parking sign out of place to steal a 10-speed bike that was locked to it.

Halprin, an avid cyclist who has been the victim of bike theft in the past, said he had to step in and stop what was happening. He pulled his car up next to the man.

But the would-be thief kept on tugging at the pole, eventually lifting it and dragging the bike away.

"I pull up a little further as he's moving," Halprin said. "I open my car door to get out. And then he decides it just not worth it.

"This was 11 a.m. Everybody was ignoring this guy. Friday. Nobody seemed to care," Halprin said.

The thief eventually dropped the bike and ran off. Halprin snatched it up and took it to his store — Celia's Jewelry at 194 Osborne St.

He's appealing for the rightful owner of the bike, which is light blue in colour, to come forward and collect it as long as the person has the right key to unlock it.

"I'd like to give it back to them," Halprin said.

He refuses to think that he did anything extraordinary, saying he feels that simply ignoring thieves sends the wrong message.

"That's why people are getting away with what they're getting away with," Halprin said.