12/21/2011 06:59 EST | Updated 02/20/2012 05:12 EST

'Vaulter' Bank Robber Reward Set At $20K

Toronto Police

A reward to nab the so-called "Vaulter Bandit," alleged to have struck 17 banks across Ontario and in Calgary, has doubled to $20,000, after the robber's tactics grew more aggressive in his latest caper this month.

Toronto police believe the Vaulter Bandit — so nicknamed because the armed suspect leaps over the bank teller's counter and grabs cash from the till — has returned to the Greater Toronto Area after making trips to pull off similar heists in Ottawa, Hamilton, Ont., and Calgary.

He has never struck in downtown Toronto.

"It's astonishing that he's been successful — that he's attempted 17 robberies without being identified or caught," said Det.-Sgt. Mike Fleischaker, of York Regional Police.

On Wednesday, the Canadian Bankers Association offered up to $20,000 for information leading to his arrest and conviction.

The man, who brandishes a gun during his robberies, struck a TD Canada branch in Vaughan, Ont., on Dec. 14. This time, police said he seemed to have altered his modus operandi slightly.

Concerned about escalation

"He's certainly willing to take it to the next level," Fleischaker said.

Police said the man stalked one of the employees at the TD bank in Vaughan, then followed her into work and ambushed her before the bank opened. The employee fought with the suspect and managed to get away.

A full-time security guard is now posted at the Vaughan branch, and co-workers said the worker is still traumatized.

Police said they're concerned about what appears to be an escalation in the robber's tactics, and that he may be becoming more violent.

"With these types of bandits, they continue until they get caught," Fleischaker said.

"We're dealing with somebody here who's probably pretty familiar with the banking environment, has been involved in robberies in the past."

The Canadian Bankers Association is also seeking tips to help solve several other robberies, most of which were committed in Toronto. Aside from the Vaulter Bandit, police are looking for three other robbers still at large — nicknamed the Blue-Eyed Bandit, the Smart Bandit and the New Year Bandit.