A 47-year-old San Francisco man was charged with murder in the kidnapping and torture of a young man whose body was stuffed into a suitcase before being dumped in the San Francisco Bay, where it was found last week, officials said Monday.

Prosecutors described the grisly details of the slaying of 23-year-old George Randall Saldivar in a motion to detain the defendant without bail that was filed Monday in San Francisco Superior Court.

Gerald Rowe was arrested Friday and charged with murder with the special circumstances of lying in wait and torture, along with charges of conspiracy, torture, kidnapping, battery with serious bodily injury, false imprisonment, possession of a firearm by a felon and drug offenses.

Investigators said a second unidentified person also participated in the killing. It’s not clear if that person has been arrested.

Saldivar’s body was discovered on Feb. 18 floating near the east side of Pier 39 along the Embarcadero. Two days later, the medical examiner determined Saldivar was a homicide victim and alerted police.

Investigators were led to a home on the 1272 block of Market Street that was registered to Rowe, Assistant District Attorney Michael Swart wrote in the court motion.

Inside the apartment, police recovered video of the shocking killing that took place between Feb. 3 and Feb. 5, prosecutors said.

The video showed Rowe and another person — only identified as an “un-named co-conspirator” having consensual sex before Rowe leaves the room and comes back to see his partner talking with Saldivar at the front door, Swart wrote.

Prosecutors said the video shows Saldivar entering the apartment and sitting in a chair where the accomplice ties Saldivar’s hands behind his back.

“The unnamed co-conspirator and defendant Rowe make a noose and put the noose over the victim’s’ neck,” Swart wrote. “The rope is then elevated over an unknown object in the room by defendant Rowe and the unnamed co-conspirator.”

Both Rowe and the co-conspirator yanked on the rope, placed a bag over the victim’s head and injected him with a narcotic officials believe may be fentanyl, prosecutors said.

Saldivar collapsed and prosecutors said the two placed him on a bed and began slapping him.

The co-conspirator then “obtains a suitcase from the closet and both place victim inside the suitcase and eventually seal the suitcase in plastic,” Swart wrote. “Defendant Rowe then eats junk food and plays his guitar over the suitcase.”

The two then pushed the suitcase into the corner of the room, where prosecutors said it sat for an entire day while the two “go about their business.”

At 2:30 a.m. on Feb. 5, the duo rolled the suitcase out of the room and onto Market Street, officials said.

Prosecutors have not identified a possible motive for the alleged killing. Rowe is scheduled for arraignment Thursday.

Saldivar kept numerous social media pages, including several Facebook pages where he identified himself as a former student at Mission High School in San Francisco.

Evan Sernoffsky is a San Francisco Chronicle staff writer. Email: esernoffsky@sfchronicle.com Twitter: @EvanSernoffsky