Updated

The Senate has postponed a key vote Monday on the controversial nominee to head the Civil Rights Division at the Justice Department, Fox News has learned.

Supporters of nominee Debo Adegbile would have needed a simple majority of 51 votes Monday to clear the way for a final vote. But the procedural vote was canceled because of a snowstorm forecast for Monday, the same day most Capitol Hill lawmakers return from their home states.

The vote has been rescheduled for midday Tuesday. If Adegbile clears the procedural vote then, after another short debate, a final vote in which he would again only need a simple majority of 51 votes to be confirmed will take place.

Sen. Bob Casey, D-Pa., joined others in his concern about Adegbile’s support for convicted Philadelphia cop-killer Mumia Abu-Jamal.

Adegbile is facing criticism for his role in supporting Abu-Jamal's 1981 death sentence being overturned during his time as acting director of the NAACP Legal Defense and Educational Fund.

“The vicious murder of Officer [Daniel] Faulkner in the line of duty and the events that followed in the 30 years since his death has left open wounds,” Casey said Friday. “After carefully considering this nomination and having met with both Mr. Adegbile as well as the Fraternal Order of Police, I will not vote to confirm the nominee.”

Abu-Jamal's death sentence has been thrown out but he remains in prison.

Widow Maureen Faulkner told Fox News she is gratified at the decision by Casey to vote against the nomination of Adegbile and that she plans to continue to lobby members of the Senate to take a similar stand.

Among the others who have expressed their objection to the nomination is GOP Pennsylvania Sen. Pat Toomey.

“The murder was not a random street crime,” Toomey and Philadelphia District Attorney R. Seth Williams recently wrote in a Wall Street Journal op-ed piece. “Abu-Jamal was an ardent supporter of the "MOVE" organization -- a racist, anarchist group founded in Philadelphia in 1972. The group's radical positions included encouraging violence against police.”