EDITOR’S NOTE: This story has been updated with a comment from the acting commissioner of U.S. Customs and Border Protection.

HARLINGEN, Texas (Border Report) — A 53-year-old Canadian woman who was arrested on charges of mailing a poison-filled envelope to the White House and to four law enforcement agents in South Texas was identified on Tuesday by the Hidalgo County sheriff, who said he received a suspicious package last Wednesday.

Hidalgo County Sheriff J.E. “Eddie” Guerra said he received an envelope on Sept. 9 that contained “a suspicious white powdery substance,” according to a news release from his office. The letter contained a Canadian postmark and “the author clearly stated a desire to harm Sheriff Guerra and three female detention officers as they too were sent letters.”

There were no injuries resulting from the letters, which were intercepted at the Hidalgo County Detention Center in Edinburg, Texas. And the substance inside the letter was identified as ricin, a deadly toxin.

Authorities also found the letters contained similar language to a letter sent on Saturday to President Donald Trump “that included the same signature block ‘FREE REBEL SPIRIT,'” the sheriff said.

“The letter along with the substance was immediately secured as a standard protocol to avoid any further contact or possible contamination to employees. The United States Postal Inspector was advised our office had received a letter with a potentially hazardous substance,” the sheriff’s office said.

Authorities identified the sender as Pascale Cecile Veronique Ferrier, a Canadian who was listed as being from Lavell, Quebec, in documents from her arrest on March 20, 2019, in Mission, Texas.

On Monday, Mission Police Investigator Art Flores told Border Report that a suspicious package containing a white substance also was sent to Mission Police Chief Robert Dominguez on Thursday or Friday.

Ferrier had been arrested by Mission police on weapon possession charges that violated her visa. She was released on May 18, 2019, to U.S. immigration authorities, Guerra said. She was then deported back to Canada but was arrested this weekend as she tried to cross the border into upstate New York

Late Tuesday, U.S. Customs and Border Protection Acting Commissioner Mark Morgan gave more details on the Sunday arrest that occurred at the Peace Bridge port of entry in Buffalo, New York. In a statement, Morgan said CBP “officers encountered a driver who stopped her vehicle in the pre-primary area, and did not pull forward to report for inspection. Officers responded to the vehicle and engaged the driver.”

Morgan said “Ferrier told officers she was wanted by the FBI for mailing envelopes with ricin to the White House and other locations.” He said that during a search of her vehicle, CBP officers “discovered a gun, knife and ammunition.”

She was immediately arrested and FBI officials were called.

“The officers’ quick action should be commended, and exemplifies what we do every day on the frontline of our nation’s borders. CBP remains committed to stopping those who come to this country with the intent to do harm, and we will continue to work with the FBI and Department of Justice on this ongoing investigation,” Morgan said.