Spending time inside the decrepit concrete box that is San Francisco’s Hall of Justice is never pleasant, but a hearing there Tuesday was particularly stomach-churning.

The perfunctory meeting in the bland courtroom lasted just a few minutes, but the reason for it couldn’t have been more important. Would a man held over for trial on eight felony counts of pimping and sex trafficking underage girls, and engaging in unlawful sex with a 15-year-old, be released as he awaited trial?

San Francisco Superior Court judges have a reputation for being too lenient in this liberal, live-and-let-live city, where it’s easy to see crimes happen before your eyes. In broad daylight. On crowded streets. With seemingly no repercussions. Think drug dealing, breaking into cars, shoplifting and chopping up stolen bicycles, to name just a few.

But this was worse. So much worse.

This was the case of 24-year-old Randall Roy Stovall, who had professed to wanting to turn his life around, if only he could be released from jail to attend a treatment facility for alcoholics while he waited for his trial to begin.

At a hearing April 5, Judge Kay Tsenin indicated she was open to releasing him. Despite the fact she’d presided over his December preliminary hearing, which was full of graphic, devastating testimony about his treatment of teenage girls. Despite the fact she had ordered him to stand trial on all the charges. Despite the fact that if he is found guilty at trial, he could face 25 years or more in state prison. Despite him not showing up for past court dates.

Gee, what could happen if she released him?

Tsenin said Stovall would have to wear a GPS monitoring device on his ankle.

But, according to Assistant District Attorney Asha Jameson, who vehemently fought Stovall’s release, the Sheriff’s Department has just two deputies to monitor the 190 people currently wearing monitoring devices. And the deputies can monitor only where the defendants are, not if they’re committing crimes. And guess who’s responsible for keeping the monitors charged? The defendants!

Tsenin set Tuesday’s hearing to iron out one final detail: how Stovall would be transported to the alcohol treatment facility. Because clearly that was the most important detail of this sordid affair.

And boy, is it sordid.

Reading court transcripts from Stovall’s December preliminary hearing was an eye-opener about the subculture of pimping and sex trafficking. (The former term is used to describe a consensual business relationship, while the latter describes a coercive one.)

The FBI calls San Francisco one of the world’s major sex trafficking hubs, yet it’s easy to live here and never think much about it.

“It’s a lot more common than people realize,” said Kim Sandoval, a human trafficking investigative analyst for the district attorney’s office. “Arrests are elusive. Prosecutions are hard to get because of the dangers to victims and their families.”

The Mission District and massage parlors throughout the city are centers of sex trafficking, Sandoval said. The crime is more widespread than the drug trade because, in the case of paid sex, the same product can be sold “over and over again.”

Girls and young women ages 16 to 22 are the most common victims, and they’re often foster youth or runaways who can be lured into sex work with gifts as simple as clothing, food and shelter, Sandoval said.

San Francisco has three “tracks,” or “blades,” the slang used to describe the city blocks prostitutes frequent. According to police who testified at the preliminary hearing, they’re Geary Street between Powell and Taylor streets; Polk Street between Post and California streets; and the busiest, Capp and Shotwell streets between 18th and 22nd streets.

Sgt. Randy Ly testified about his interview with a 15-year-old girl, who’d called police in January 2016 to report that Stovall was was trafficking her. The girl did not testify at the preliminary hearing.

She told police about being recruited in Oakland by a prostitute who worked for Stovall. The woman even brought food from Jack in the Box to her during lunchtime at her East Bay high school, where she was in her sophomore year.

The girl agreed to meet Stovall, and he drove her into San Francisco and gave her marijuana and cocaine in the car. She reported to police that Stovall told her rich people were arriving in the city for the Super Bowl, and there was a lot of money to be made.

Lowlights of the girl’s long story include multiple nights of “walking the track” in the Mission, Stovall initiating oral and vaginal sex with her at a Motel 6 in Oakland, and him firing a gun three times at another car during a road-rage incident while she was in the vehicle.

So, you know, a real stand-up guy.

Eventually, the girl called her father from the Mission track, telling him she wanted out. He told her to call 911, and the dispatcher directed her to the Mission Police Station.

Stovall was arrested at Shotwell and 18th streets and charged with human trafficking, pimping and statutory rape. Bail was set at $250,000, and Stovall posted it and was released.

In April 2016, he was arrested in Oakland during an undercover prostitution sting. In May 2016, he was detained in Santa Clara County after leaving a motel room with two 16-year-old runaways and an 18-year-old prostitute. He failed to appear in court in either case.

In August 2017, he was arrested for attempted robbery and assault of a San Francisco Muni driver. He again posted bail and was released. He again failed to appear in court.

A 17-year-old girl then reported to police that Stovall had trafficked her in early 2018, posting pictures of her in her underwear in online sex ads and arranging for men to meet her at a Travelodge hotel in the city. A warrant was issued for his arrest, and he was picked up in June — he had young prostitutes in his car.

Finally, Superior Court Judge Victor Hwang refused to set bail, and Stovall has been in custody ever since.

Tsenin presided over the preliminary hearing in December, during which the 17-year-old girl testified. The judge ordered Stovall to stand trial on eight felony charges. In our incredibly slow criminal justice system — some cases at the Hall of Justice have been dragging on for more than six years — there’s no telling when Stovall’s trial will start.

Trials in which defendants are in custody tend to start more quickly. Those for defendants who are not in custody can take longer to schedule, and victims’ memories and willingness to testify can fade.

At the hearing Tuesday, Stovall’s father sat in the front row, alternately closing his eyes, shaking his head and pursing his lips when his son’s transgressions were described.

Stovall’s public defender, Carmen Aguirre, said some of the crimes had happened when Stovall was just 21 years old, when his brain wasn’t fully formed. (Imagine how confusing it was for the 15-year-old girl!)

“There are some redeeming qualities in Mr. Stovall,” Aguirre told the judge, adding he didn’t use violence or force with the girls.

Jameson wasn’t buying the contention that Stovall would live a good, peaceful life while out of custody waiting for trial.

“Every single time the defendant has been arrested, we’ve accumulated more victims,” she said. “Any release of Mr. Stovall would be an incredible public safety risk.”

Perhaps the smartest thing Jameson did was alert advocates for victims of sex trafficking, a few of whom showed up to the hearing. I was there too. Tsenin, whose last day on the job before retiring happened to be Tuesday, ended up making the right decision.

“My job is to protect society, so I’m going to deny your motion,” Tsenin said. “Sorry.”

Don’t be sorry, judge.

Stovall’s dad formed his hand into a phone shape, held it up to his ear and mouthed “call me” to his son before quickly leaving the courtroom.

The bailiff put handcuffs on Stovall and led him out of the courtroom, back to his holding cell. Exactly where he belongs.

San Francisco Chronicle columnist Heather Knight appears Sundays and Tuesdays. Email: hknight@sfchronicle.com Twitter: @hknightsf