West Palm Beach, Fla. — Prosecutors cannot use secretly recorded video allegedly showing New England Patriots owner Robert Kraft engaging in massage parlor sex, a judge ruled Monday, striking a serious blow to their case against him and others charged with soliciting prostitutes at the Orchids of Asia Day Spa.

In his 10-page ruling, Judge Leonard Hanser wrote that Jupiter police detectives and the judge who issued the search warrant allowing the secret installation of cameras at the spa did not do enough to minimize the invasion of privacy of customers who only received legal massages. Hanser also ruled that detectives cannot testify about what they saw on the video or when they stopped Kraft.

If upheld on appeal, Hanser's ruling could lead to prosecutors dropping the second-degree misdemeanor cases against Kraft and other men charged with paying for sex at the Orchids of Asia Day Spa. Kraft, 77, has pleaded not guilty, but issued a public apology.

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"The fact that some totally innocent women and men had their entire lawful time spent in a massage room fully recorded and viewed intermittently by a detective-monitor is unacceptable," Hanser wrote. He said the judge should have given the officers explicit instruction for how to monitor the video.

Kraft's attorneys declined comment. Palm Beach County State Attorney spokesman Mike Edmondson said prosecutors were still reviewing the ruling but would appeal if they found a legal basis. The ruling is similar to one in a neighboring county, where a judge also suppressed video of men allegedly paying for massage parlor sex.

Jupiter was part of a multi-county investigation of massage parlor prostitution and possible human trafficking that resulted in the arrests of about 300 men and the closure of 10 spas stretching 130 miles from Palm Beach to Orlando. The spa owners and some employees have been charged with felonies. Prosecutors have conceded they found no evidence of human trafficking at the Jupiter spa and no one has been charged with it elsewhere. Neither Kraft nor the 24 other men charged in the county were specifically targeted.

Hanser had already ruled that the Kraft videos cannot be released publicly until his trial is underway or the case is settled or dismissed.

NFL officials have said they are watching the case, but have not disciplined Kraft.

According to police records, Kraft, a widower worth $6 billion, was chauffeured to the Orchids of Asia spa on the evening of Jan. 19, where officers secretly recorded him engaging in a sex act with two women and then handing over an undetermined amount of cash.

Investigators said Kraft returned 17 hours later and was again videotaped engaging in sex acts with a woman before paying with a $100 bill and another bill, police said. On Monday, prosecutors consolidated the two cases into one charge.

Prosecutors offered to drop the original charges if Kraft entered a diversion program for first-time offenders, as some others charged have. That would include an admission he would be found guilty if the case went to trial, a $5,000 fine, 100 hours of community service and attendance in a class on the dangers of prostitution and its connection to human trafficking. Prosecutors have said the fine and community service are required by law and are not negotiable.

Hanser has ordered Kraft to appear in court for a May 21 pretrial hearing. It is unclear how Monday's ruling will affect that hearing.