By Tony Hanson

PHILADELPHIA (CBS) — A judge declared a mistrial on Tuesday after a jury was unable to reach a verdict in a case against the alleged Kensington serial rapist.

Prosecutors were planning to retry the case against 32-year-old Marcos Camacho, who they accuse of raping three women and attempting to rape a fourth woman during an eight-day period in November, 2011.

The jury heard from all four alleged victims, including a woman who testified she was grabbed off the street and raped at knifepoint in the defendant’s car.

“The knife was put to her, she was grabbed by the hair,” says Prosecutor Jack O’Neill. “She was forced into the car, the car that the defendant was ultimately arrested in, and she was raped.”

The evidence in that case included DNA. But Defense Attorney Alfonso Gambone says Camacho admitted to having sex with the woman. He claimed she was a prostitute and said it was consensual, but he didn’t pay her.

Gambone argued this case was about getting even.

“The other three, my client maintains, that he does not know these individuals,” Gambone says. “He doesn’t know who they are, he doesn’t know why they are accusing him of rape. “

There was no DNA evidence in any of those three cases.

Camacho remained in custody. A new trial date was not immediately set.