OTTAWA -- Quebec resident Pascale Ferrier has been identified as the suspect alleged to have sent letters containing the poisonous substance ricin to the White House and different locations in Texas, including a police department, CTV News has confirmed.

A team that specializes in biohazards swarmed a Montreal-area condo Monday morning, evacuating several units as they looked for evidence connected to the ricin-laced letter sent to U.S. President Donald Trump.

The letters were intercepted before reaching their destination, and the exact number is "in flux," officials say.

Ferrier, 53, was arrested at the New York-Ontario border on Sunday while trying to cross the border into Buffalo, N.Y.

Ferrier was initially expected to appear in court Monday afternoon in Buffalo to face federal charges in the U.S., but sources tell CTV News the appointment was postponed to tomorrow.

Ricin is a deadly substance extracted from castor beans. It’s a plant that is not restricted and is easy to grow. With enough exposure, the poison can be fatal within 36 to 72 hours, and there is no antidote.

Ferrier, originally from France, became a Canadian citizen in November 2015. According to sources, she is a computer programmer.

She moved back to Laval last spring, weeks after being released from a Texas prison.

Court documents show in 2019 she was charged with unlawfully carrying a weapon and knowingly using a fake Texas driver’s license. Ferrier spent three months in jail according to arrest records.

The Texas Police Department that laid those charges was also sent a letter with ricin last week.

An RCMP investigation was carried out at Vauquelin Boulevard, a residential street located south of Montreal in St-Hubert, Que.

“There’s a link between the female suspect that was arrested in Buffalo, New York yesterday and this residence,” RCMP Cpl. Charles Poirier said Monday, explaining to reporters in St-Hubert that police had a search warrant for the residence.

An RCMP team dedicated to chemical threats and explosives is leading the investigation, with local police and fire units also at the property.

CTV News public safety analyst Chris Lewis told CTV News Channel on Monday that police will "know more about her quickly than she knows about herself, from her online presence, to her background.”

The motive will be a main part of the investigation, he said.

“Are there mental health issues involved or is it a bigger plot that she's somehow a part of and maybe acted on someone else’s behalf?” he said.

This isn’t the first time a U.S. president has been sent ricin. Letters addressed to former president Barack Obama containing the substance were intercepted on two separate occasions in 2013.

"There will be very serious charges. Ricin is a very deadly [substance], a very little amount of it can kill people and we’ve seen attacks using it around the world over the last 20 years, so pretty serious stuff," said Lewis.

None of the charges have been proven in court.

With files from CTV News’ Annie Bergeron-Oliver and Alexandra Mae Jones