San Francisco prosecutors are objecting to a defense request to allow high-profile political consultant Enrique Pearce to avoid jail time for possessing child pornography — and to instead be monitored at home by a private company that would outfit him with an electronic ankle bracelet.

Pearce, whose clients included Mayor Ed Lee and Supervisors Jane Kim and Norman Yee before his arrest in May 2015, is due back in court Friday. It will have been six weeks since Superior Court Judge Rene Navarro postponed sentencing for the 43-year-old defendant, who was set to plead guilty to possession of hundreds of images of child pornography — including what prosecutors called “sadomasochistic practices being conducted on very young children.”

The delay came after Sheriff Vicki Hennessy balked at enforcing a portion of the agreement that Pearce cut with the judge to plead guilty in exchange for a sentence of six months of home detention.

Hennessy’s office argued that people convicted of certain crimes, including child pornography, don’t qualify for electronic monitoring in San Francisco under her department’s policies.

On Tuesday, District Attorney George Gascón’s office filed a motion backing Hennessy’s stance, saying any move to allow Pearce to serve his time at home “over the objections of the Sheriff’s Department ... represents an illegal sentence to the extent that it would usurp the (sheriff’s) statutory authority.”

“The Sheriff’s Department alone has the statutory authority to decide how and where inmates serve their jail sentences,” Assistant District Attorney Brad Allred wrote.

The prosecution’s motion followed a letter to the court Monday from defense attorney Douglas Horngrad laying the groundwork for Pearce’s home detention, specifically addressing the judge’s concern that it be “commensurate with the supervision” provided by the Sheriff’s Department for such cases.

Horngrad said he had arranged for a company called Intercept to supply an electronic ankle bracelet for Pearce and to do the monitoring to make sure he stays home. In addition, the defense attorney said, Pearce would be checked on by a retired San Francisco police inspector, Stephen Gudelj, who would make “random unannounced searches.”

The only way that can happen, legal experts say, is for Pearce to be sentenced to probation. It would amount to an end run around the sheriff — who would be cut out of the monitoring.

Allred argued to the judge that the proposal “would not result in the accrual of custody credits” demanded by the severity of Pearce’s crimes “and would not be considered the equivalent of County Jail.”

Prosecutors originally pressed for state prison time for Pearce, and they still want him put behind bars in County Jail. But under state rules, they didn’t get a say-so in the plea deal he agreed to in December — he could simply admit to all four charges against him once Navarro told him what the likely sentence would be.

Those charges are two counts of distributing child pornography, one count of buying or receiving stolen property, and one count of possession or control of child pornography, with allegations of possessing more than 600 images of someone under 18 and possessing matter that portrayed sexual sadism or sexual masochism involving someone under 18.

Now it’s up to Navarro — a retired Santa Clara County Superior Court judge on temporary assignment in San Francisco — to decide whether he will carry out that deal.

San Francisco Chronicle columnists Phillip Matier and Andrew Ross appear Sundays, Mondays and Wednesdays. Matier can be seen on the KPIX-TV morning and evening news. He can also be heard on KCBS radio Monday through Friday at 7:50 a.m. and 5:50 p.m. Got a tip? Call (415) 777-8815, or email matierandross@sfchronicle.com. Twitter: @matierandross