Police stayed at the Oval to check for suspicious packages after the crowd cleared on Friday. (CBC)

Halifax Regional Police have released a recording of the 911 bomb threat call that forced the cancellation of one of the Canadian Cancer Society’s biggest fundraisers on Friday night.

Police said they hope someone can identify the caller through his voice. During the call the man alluded to the Boston Marathon bombings.

On the tape the man can be heard saying "Remember the Boston bombing? Well, that’s going to f--king happen up here in Halifax."

Police said they traced the call to a payphone at the corner of Spring Garden Road and South Park Street. Officers were at the payphone within two minutes of the call, but they couldn’t find the suspect.

Nearby, nearly 700 people were gathered at the Oval on the Halifax Common for the Relay for Life. Police said it was the only event similar to the Boston Marathon taking place in Halifax Friday night.

Police met with the organizers and the fundraiser was called off.

Sunday's Walk to Fight Arthritis was also cancelled. On Facebook, organizers blamed the bomb threat.