Robert Kraft Prosecutors Refused to Join Effort to Block Spa Video Release

Robert Kraft's bid to make sure his prostitution sting video doesn't see the light of day might be a little more difficult ... because prosecutors are refusing to play ball.

Sources familiar with the case tell TMZ ... the State's Attorney's Office in Palm Beach County declined to join in on the motion Kraft and 14 other suspects filed Wednesday in Florida ... seeking to prevent the release of any evidence, including video footage from inside the Orchids of Asia spa.

This is a big deal because if prosecutors were on board with the motion to protect the evidence, it would be much more likely the judge would sign off on it. However, prosecutors opted to let Kraft and the other alleged Johns fly solo with their motion, so it's unclear if they'll get their wish.

This begs the question -- why wouldn't the State's Attorney want to cooperate in the effort to keep evidence under wraps?? Especially considering it's an open investigation where police have, very publicly, claimed to be concerned about alleged victims.

We put that question to the State's Attorney's Office, and got a "no comment."

As we reported ... Kraft and the other suspects in the sting were offered a plea deal. It would require Kraft to complete a course about prostitution, 100 hours of community service and submit to an STD test, while also admitting he'd be found guilty if it went to trial. In exchange, the charges would be dropped.

It's pretty clear to us ... the deal's a non-starter for Kraft because it would be just like being convicted -- at least under the offered terms. It seems prosecutors want leverage over Kraft in negotiating a plea deal ... and the video is their weapon.