Mike Quigley

For the second time in less than a week, suspicious letters containing an unknown substance were delivered to Reps. Jan Schakowsky and Mike Quigley's district offices.

According to a spokesperson, Schakowsky’s office in suburban Skokie received a suspicious envelope Wednesday, marking the second time in less than a week that her office had been targeted by an unknown individual.

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More than three dozen members of Congress, including several from Illinois, were targeted with suspicious envelopes in recent days, and Schakowsky’s office was again evacuated Wednesday after an unknown substance was observed coming out of the envelope it received.

A hazmat team was called to the scene, and an investigation is underway into the incident, in conjunction with Skokie police and U.S. Capitol police.

According to a Quigley spokesperson, Chicago police and Capitol Police were notified after his Chicago office received a suspicious package on Wednesday.

“This is clearly another effort to scare and intimidate elected officials, public servants, and voters in the lead-up to the coming midterm elections," Quigley said in a statement. "I am again calling on my colleagues and political leaders on both sides of the aisle to condemn political violence in the strongest of terms and turn down the temperature of political discourse.”

In last week’s incidents, most of the envelopes had been postmarked with the phrase “Thinking of You” and were sent through a north Texas mail processing center. Wednesday’s incident featured a different type of envelope, according to a spokesperson, though it wasn’t specified what the envelope looked like.

Schakowsky and Quigley were among numerous members of Illinois’ Congressional delegation that received suspicious letters in the last week, along with Rep. Delia Ramirez, whose West Chicago office received a note. Rep. Brad Schneider’s Lincolnshire office was also targeted, and Rep. Robin Kelly also received a suspicious letter, according to her office.

According to The Guardian, more than three dozen members of Congress have been targeted in recent weeks, including Senate Minority Leader Chuck Schumer and House Minority Leader Hakeem Jeffries.

Republican Texas Sen. Ted Cruz and Nebraska Sen. Pete Ricketts were also targeted by letters.

There have been no arrests made in the case, and investigations remain underway.