A teen sex fiend who police say tried to rape a Harlem woman last week already had two open cases for forcible touching, prosecutors said

Sanjay Jaggernauth, 16, was arraigned Monday in Manhattan Supreme Court for the attack on a 40-year-old stranger last Saturday.

He allegedly followed the woman to her apartment from the West 145th Street subway station at about 6 a.m.

She heard Jaggernauth’s steps behind her and tried to pick up her pace — but the teen followed her into her building and up a flight of stairs.

“The defendant grabbed at the woman’s jacket with his hands, which the woman had zipped up, trying to pull it off,” according to the criminal complaint.

Assistant District Attorney Megan McDonald said that during the tussle Jaggernauth pushed her against a wall then down an entire flight of stairs.

Surveillance video shows Jaggernauth and the woman stumbling down the stairs, she said.

McDonald added that the defendant has two open forcible touching cases currently pending in family court.

The DA’s office hit the teen creep with 20 counts of burglary, attempted rape, assault and other charges and plans to present the case to a grand jury for indictment.

But first they have to persuade a judge at an upcoming hearing not to send the attempted rape case to family court, where he would be treated as a minor.

Defense lawyer Donna Henken said that Jaggernauth is a full-time student who lives with his father.

Police say that Jaggernauth may have been responsible for an earlier sex attack in the same area — but sources say that cops dragged their feet investigating.