Senate Sergeant-at-Arms Terrance Gainer said he is looking into the possibility of bringing charges against the man suspected of sending letters with suspicious powdery substances to two Senators, even though he may already be serving a life sentence in a New York prison.

Michael Taffinder was sentenced to 30 years to life in 2002 for multiple counts including murder and attempted murder.

He shot an 18-year-old stripper after she left the club where she worked, leaving her paralyzed and a taxi driver dead, according to reports written at the time in New York newspapers.

“We’ll work with the FBI to see whether this individual should be further prosecuted for his evildoing,” Gainer said in an interview Tuesday. “I always think it’s worth it. … It discourages others.”

Police allege Taffinder sent two envelopes that contained threatening language and a powdery substance from the Great Meadow Correctional Facility in Comstock, N.Y., to two Senators’ offices in Washington, D.C. The substance was not found to be dangerous.

“These incidents are reminders that the entire Senate community needs to remain vigilant in handling mail, recognizing suspicious items, and knowing what immediate actions to employ if faced with suspicious mail in the office,” the Office of the Sergeant-at-Arms wrote in an e-mail to Senate offices.

Gainer said his office has warned district employees too.