The feds slapped him with charges of attempted robbery and of carrying a firearm during a crime of violence.
His attorney, Thomas Fitzpatrick, confirmed yesterday that Walker has a guilty-plea hearing scheduled for Monday, but declined further comment.
The U.S. Attorney's Office would not comment yesterday.
According to the FBI affidavit, the feds got wind of Walker after a cooperating witness said Walker had approached him to set up drug dealers for Walker to rob. Since May 6 of last year, the witness continued to meet with Walker, under the FBI's monitoring.
A few days later, Walker told the witness he had a drug dealer to target. Walker came up with a plan in which he would plant drugs in the dealer's car, arrest the dealer, then take his keys.
That plan was executed May 21, the affidavit says. Walker left the Narcotics Field Unit and drove to the drug dealer's house on Florence Avenue near 57th Street, arriving about 11:40 p.m. The witness met him there.
The two then entered the Kingsessing home and walked out about six minutes later with about $15,000 - alleged proceeds of drug sales, the affidavit says. He had his service gun on him. The witness came out with about five pounds of marijuana.
Walker was arrested outside the home. He admitted planting cocaine in the dealer's vehicle, taking the house key and stealing the cash, the affidavit says.
His arrest has caused a fallout in state drug cases. A Common Pleas judge in November overturned 53 drug-related convictions because of Walker's involvement. Then, on Dec. 6, the District Attorney's Office withdrew 12 drug cases involving Walker.
On Twitter: @julieshawphilly