A Canadian woman has been identified as the suspect behind the incident where a letter containing ricin was sent to the White House.

Pascale Ferrier, of Quebec, Canada, was the woman arrested Sunday at the Peace Bridge border crossing near Buffalo, New York, for allegedly sending a poisoned letter to President Donald Trump.

Global News of Canada reported that there is a major police operation in conjunction with the investigation.

A swarm of police crews arrived outside a residential building in Montreal at 10 a.m. on Monday.

Royal Canadian Mounted Police Cpl. Charles Poirier confirmed that the police were conducting a search warrant of the condo concerning “suspicious packages” mailed to the White House and “other areas” of the U.S.

“There’s a link between the female suspect who was arrested in Buffalo, N.Y. yesterday and this residence,” he told reporters from the scene. “We can’t confirm that it’s actually her residence. We know she’s linked to that address, but the nature of that link, that’s yet to come.”

The ricin-filled letter was intercepted at a government facility that processes mail addressed to the White House and the president.

U.S. authorities say Ferrier was carrying a gun and arrested by U.S. officials. Federal prosecutors in Washington, DC, are expected to bring multiple charges against her.