SAN FRANCISCO (CBS SF) — A San Francisco man accused of sexually attacking a woman in her home while she slept was convicted of a felony charge this week and faces a life sentence, the San Francisco District Attorney’s Office said Thursday.

Roberto De Trinidad, 30, was convicted by a jury Wednesday afternoon of assault with intent to commit rape or other sexual acts during the commission of a residential burglary, prosecutors said.

The incident occurred on Aug. 8, 2013, when the victim told police that she came home after work and fell asleep watching television, according to court records.

She said that she awoke to pressure and pain on her backside, and noticed a substance that she suspected was semen on her buttocks. She then saw a man walk out of the room and screamed, at which point her roommate woke up and looked for the apparent intruder but did not find him.

The woman did not contact police until a few days later, at which point officers responded and took samples from stains on her bedding that later returned a DNA match to De Trinidad, prosecutors said.

“These cases are difficult for victims and a challenge for investigators,” Assistant District Attorney Brad Allred said in a statement. “Everyone worked together to ensure justice was served and that a violent man was taken off the streets.”

“This victim had an incredibly traumatic experience,” said District Attorney George Gascón. “Her courage to come forward ensures this dangerous predator can’t harm others.”

De Trinidad’s defense attorney, Emily Dahm, said that her client testified during the trial that he had gone to the victim’s apartment believing he was going there for a consensual sexual encounter with a “conscious, sober, willing and interested participant.”

“It was only 14 months later that he learned he had been accused of anything,” Dahm said.

Dahm said De Trinidad has a prior criminal record but no history of sex crimes.

While he was convicted of one charge in this case that carries a mandatory life sentence, she noted that the jury hung on other charges alleging sex crimes after nearly three full days of deliberation.

“We will be appealing with vigor and I look forward to him having a new day in court in which he can establish his innocence,” Dahm said.

In October 2013 the Marin Independent Journal reported that Roberto Antonio De Trinidad, 27, of San Francisco was booked into Marin County Jail on suspicion of vehicle theft, attempted burglary, possession of burglary tools, driving without a license and providing false information to police after an interrupted residential burglary in Mill Valley.

No sentencing date has been set, according to prosecutors.