The RCMP is now asking the public to help identify two men it has been trying to track down for nearly three months, but reporters were told on Wednesday morning there is "no imminent threat" to the public.

Supt. Lise Crouch, speaking at a news conference in Milton, Ont., said a witness saw what was believed to be "suspicious behaviour of these two males while on the John Street bridge," which is near the Rogers Centre as well as a busy rail line, on the afternoon of Aug. 31.

RCMP Supt. Lise Crouch says police need to speak with the two men in question to rule out any criminal intent. (CBC) Crouch wouldn't say what the two men were doing that was suspicious but said police have several questions they would like to put to the men. Crouch denied the suggestion that the men's race is a factor in the investigation.

"It has nothing to do with brown skin. It has everything to do with what they were observed to be doing by the complainant," Crouch said, adding the RCMP did conduct a followup interview with the person who witnessed the suspicious behaviour.

"What was described for us is enough to continue in the investigation to speak with those two males," she said.

​Crouch said police have been "pursuing all avenues" to find the men, including obtaining surveillance video and speaking with other people who were in the area at the time.

Six other suspicious incidents were reported in the area of the pedestrian bridge around the same time that day. In each of those incidents, police spoke with those involved and ruled out any criminal wrongdoing.

Crouch said the two men are considered persons of interest, and police just want to speak with them

"We haven't been able to put this one to rest," she said.

PM in area on day of incident

Then prime minister Stephen Harper was at the Rogers Centre on the same afternoon, CBC News reported at the time. He was watching batting practice before the Toronto Blue Jays played the Cleveland Indians.

Crouch said for now, there's no link between the two events and that police are investigating merely because an online report filed to the RCMP.

Crouch also said she doesn't believe this investigation should shake the public's confidence in the RCMP to track people down.

"I don't think the public should be concerned at this time," she said.

Police describe the men they are looking for as:

20 to 30 years old.

Medium build.

Brown skin.

One man was wearing blue jeans, a green and white striped shirt, and was carrying a backpack. He had on blue Adidas shoes with yellow laces.

The other man was wearing dark blue jeans and a blue and yellow striped shirt with purple stripes. He also had sunglasses hanging on his shirt. He was wearing blue Puma shoes with yellow laces.

Online report led to search

The John Street bridge is a busy passageway during the Blue Jays baseball season. (John Rieti/CBC) The RCMP's nearly three-month search for the two men was triggered by an online alert known as a suspicious incident report (SIR).

The RCMP said the SIR was filed by a "private sector partner" that owns critical infrastructure in the area of the bridge, though a spokesperson declined to reveal any further details. The John Street bridge is a busy access point to the Rogers Centre, CN Tower and Ripley's Aquarium, but it also crosses a busy rail corridor used by GO Transit, Via Rail and others.

SIRs were piloted in 2008 and made web-based in 2010 and have led to at least one arrest, the RCMP said.

An article about SIRs published last year in The Communicator, a publication that serves Canada's agricultural industry, suggests it can be used to report a variety of suspicious behaviour, from people appearing to case a location to the theft of uniforms or identification tags.

"These types of incidents would not normally garner the attention of law enforcement if obvious crimes were not committed," writes Robert Zawerbny, a criminal intelligence research specialist with the RCMP.

"[The SIR] is designed to collect information on suspicious incidents that may be related to criminality, and, as such, pose threats to critical infrastructure."