Toronto police are searching for four suspects after a rash of bank robberies in the Greater Toronto Area.

According to Toronto Police Service's Hold Up Squad, there has been a 75-per-cent spike in bank robberies during the first three months of the year, compared to the same period last year.

Police said the four bank robbery suspects are being sought in connection with 10 to 12 "unresolved" thefts this year.

"I would say we are having some serial bank robberies," Insp. Mike Earl said in a statement on Tuesday.

Police said one of the suspects, nicknamed "The Mummy Bandit," is believed to have robbed seven banks since October 2013.

"We have great concern about this individual because he has an edged weapon and he has used what we believe to be a handgun on every occasion," Earl said.

Police believe his last bank robbery was committed on March 27 in the Carlton and Yonge streets area.

The second suspect is nicknamed the "Pleather Bandit," because police believes he wears an imitation leather jacket. The Hold Up Squad believes he robbed a Bank of Montreal branch located at King Street West and Dufferin Street at around 4 p.m. on March 11.

Earl said the suspect made a verbal threat and handed a note to the teller, indicating he had a handgun.

The third suspect is nicknamed the "Man in Black." According to police, he robbed a bank located at 110 Spadina Ave. on Jan. 15. Police said he approached a teller with a note indicating he was armed with a handgun.

The final suspect is nicknamed the "Box Cutter." Police believe he robbed three banks in March.

"In each case, he approached a teller and produced a knife that tellers described as a box cutter," Earl said.

The "Box Cutter" is described as white, between 35 and 40 years of age and between 5'9 to 6'0 tall. During the March bank robberies, police said he wore a dark winter coat and scarf around his face with a toque.

Police said the "The Mummy Bandit" walks with a "certain gait," is between 20 and 30 years of age, and is between 5'6 and 5'10 tall.

The "Pleather Bandit" is described as brown or black, between 40 and 50 years of age, and speaks with an accent.

Bill Crate, the Canadian Bankers Association director of security and intelligence, said his organization will increase Crime Stoppers payout for information leading to the suspects' arrest by 50 per cent.

"The desperation and unpredictably of this crime is what makes it so dangerous to our employees and customers," he said in a statement. "My message to bank robbers and potential bank robbers is that, if you rob a bank, you will be caught and made accountable."

Anyone with information is asked to contact the Hold Up Squad at 416−808−7350416−808−7350 or Crime Stoppers at 416−222−TIPS416−222−TIPS (8477).