Parliament Hill evacuation in Ottawa may have been prompted by hoax or bad tip, sources say

An investigation into a "potential threat" that led to the lockdown of Parliament Hill for a time was in its second day Sunday, after police in Ottawa determined there was no danger to public safety.

Police initially deemed that the threat Saturday afternoon was credible. Members of Parliament, senators and their staff were told to "shelter in place" as officers closed off streets while they investigated a "suspicious incident" and a "potential threat in the Parliament Hill area."

Since then, multiple sources briefed on the situation have told CBC News that police are now investigating whether the source of the threat was a hoax. They're also trying to determine if the tip that led to the massive police response was just a bad tip, according to the sources, who spoke on the condition they not be named because they're not authorized to go on the record.

The sources also say there's no threat to national security.

As of Sunday afternoon, police have not announced any arrests or charges. The sources said charges, if any, aren't imminent.

Incident initially called a'potential threat'

A senior government source briefed on the situation confirmed the initial tip for the "suspicious incident" was received Saturday afternoon from the intelligence branch of the Canada Border Services Agency (CBSA), a detail that was first reported by Global News.

CBSA warned the potential threat to the parliamentary precinct involved possible explosives in vehicles parked near Parliament Hill, the source said.

Law enforcement sources said the potential threat was treated as credible at the time and seen as serious. An investigation involving the Ottawa Police Service (OPS), Parliamentary Protective Service (PPS) and the RCMP, among others was launched.

At 12:55 p.m. ET, the notice to shelter in place was sent to all parliamentarians and parliamentary employees by PPS which leads the security operations in the parliamentary precinct alerting them to what the service called a "possible threat." Parliament Hill was also evacuated.

In Ottawa's downtown core, city police closed Wellington Street between Elgin Street and Bronson Avenue, as well as Metcalfe Street between Albert and Slater streets.

Senior government sources told CBC News that Prime Minister Justin Trudeau and Public Safety Minister Marco Mendicino were both briefed on the incident. At the time, Trudeau was in Los Angeles about to head back to Canada following the conclusion of the Summit of the Americas.

By 3:35 p.m., police tape that blocked access to Parliament Hill started coming down.

"Following an investigation, no public safety threat was identified," Ottawa police said in a statement that afternoon, adding that two vehicles of interest and two persons of interest were located.

The sources said the vehicles were "cleared" and any potential threats they posed were unfounded.

Still no threat to public safety: police

The investigation by multiple law enforcement agencies on Saturday afternoon began as what one source called "national security" in nature.

"By the very nature that the initial threat was related to Parliament Hill, and was related to potential explosives, it was initially treated as a national security threat," the source said. "Was it a 'major investigation' initially when the threat came in? One hundred per cent. We didn't know how serious the threat was.

"Since then, the threat has been proven not to be borne out. Would we characterize it as a 'major national security investigation' happening right now? Absolutely not," the source said Sunday afternoon.

On Sunday, the OPS, which is leading the investigation, wouldn't provide any updates, and referred CBC News to the statement the police service issued Saturday that said "the investigation into this matter continues," reiterating there is no risk to public safety.

The sources said an investigation is ongoing to determine the origin of the threat.

Also Sunday, the RCMP said that "for privacy and operational reasons, the RCMP does not confirm, deny or release information relating to criminal investigations until charges are laid. Only when an investigation results in criminal charges, would the RCMP confirm its investigation, the nature of any charges laid and the identity of the individual(s) involved."

The RCMP emphasized "there is no threat to the citizens of Ottawa or Parliament Hill at this time."

CBSA said in a statement it "does not confirm, deny or comment on ongoing investigations or policing matters," referring questions to PPS and the OPS.