Manuel Dejesus, a transient originally from El Salvador, was arrested Jan. 16 following the alleged attack on the girl that day inside a public restroom at Garfield Park in the Mission District.
Police said Dejesus is known to frequent the area of the nearby Cesar Chavez Street and also goes by the name Manuel Martir.
While Dejesus was in custody, police investigating the Dec. 21 assault of a 46-year-old San Francisco woman, also in the Mission District, found a vehicle in the area of that attack with evidence identifying him as the suspect in that case, police said. Police did not elaborate on what evidence had been found.
Dejesus had been booked into the county jail under the name Manuel Martir for the Jan. 16 attack, but investigators since discovered the two names belonged to the same person, police said. On Jan. 26, police arrested Dejesus in jail in connection with the Dec. 21 attack.
According to police, the 46-year-old woman was allegedly picked up by Dejesus in the Mission District and driven to the 1200 block of Vermont Street, where he allegedly struck her in the head with a weapon, sexually assaulted her and dumped her unconscious body on the sidewalk.
The woman was treated at the hospital for injuries to her face and neck, and she has since been released.
Prosecutors have charged Dejesus in that case with attempted murder, rape, sexual penetration by a foreign object, battery, assault with deadly weapon and false imprisonment, according to San Francisco District Attorney's Office spokesman Brian Buckelew.
He is alleged to have used a broken glass bottle to strike the woman, Buckelew said.
For the alleged assault on the 17-year-old girl, Dejesus has been charged with kidnapping, rape, sexual battery by restraint, assault with a deadly weapon for allegedly using a knife during the attack, false imprisonment and robbery, according to Buckelew.
Dejesus has pleaded not guilty to all the charges in both cases, Buckelew said. Bail is set at $1 million in each case, and Dejesus also has a no-bail status for allegedly violating his probation after being convicted in April 2008 of second-degree burglary. He is due back in court on both cases Feb. 11.
Police said they are still seeking alleged accomplices in the attack on the 17-year-old girl, who had been walking home when she was allegedly dragged by Dejesus and another man into the restroom.
The second man is described as a Hispanic man with wavy black and gray hair, between 40 and 50 years old, 5 feet 6 inches tall, and about 180 pounds.
A third man may have acted as a lookout in that attack, police said.
Anyone with information is asked to call the department's Sexual Assault Detail at (415) 553-1361 or the anonymous tip line at (415) 575-4444.