Bill Cosby became a central figure in the Montgomery County district attorney's race Tuesday as Democrat Kevin Steele began airing TV ads attacking Bruce Castor for failing to charge the comedian with sexual assault a decade ago.

Castor, who was D.A. when former Temple employee Andrea Constand alleged that Cosby had drugged and molested her at his Cheltenham home, said in 2005 that the case was "weak" due to a lack of physical evidence and Constand's delay in reporting it.

In recent interviews, Castor has said he believes that Cosby was being "deceptive" and that he thought Constand would have more success in a civil case, which she later settled for an undisclosed sum.

As Castor campaigns to reclaim the D.A. post, Steele, the county's first assistant district attorney, unveiled a 30-second campaign ad alleging that Castor "was not looking out for the victims."

"Many more victims came forward, and Castor admitted he could have used their testimony against Cosby. But Castor didn't even try," the announcer says.

In an email Tuesday, Castor called it "predictable craziness from a desperate candidate."

"Mr. Steele is still a prosecutor and could have moved against Cosby anytime after the additional evidence became available a year or so ago. Yet he did nothing," Castor wrote. "Now the election rolls around, and somehow it's my fault?"

Voters go to polls Nov. 3.

Steele had not spoken publicly about Cosby before, and his boss, District Attorney Risa Vetri Ferman, has declined to confirm or deny whether her office was considering reopening the case.

Legal experts say the criminal case against Cosby is stronger now that dozens of women have come forward with similar allegations of being drugged and groped or raped from the 1970s to the 2000s.

The statute of limitations has expired on almost all of those cases, but for Constand, the clock runs out in January.