A 20-year-old student at John Jay College of Criminal Justice, who says she's been sexually brutalized by human traffickers in Brooklyn since 2003 starting when she was just 13, finally told her secret to her college professor, resulting in Wednesday's indictment against four men in Brooklyn.

Prof. Jeff Kern, a former prosecutor in the Brooklyn District Attorney's office, said the woman first confided in him about a year and a half ago, and he slowly convinced her to take her story to the authorities.

"She was a diamond in the rough, an excellent student," Kern told PIX 11. "She aced my class." Kern told us the woman revealed she was essentially living a "double life"--going to school--and then sneaking out of her family home in Crown Heights in the evening to perform sex acts for various men, under threat from 31-year old defendant, Damien Crooks.

Prosecutors say Crooks and another suspect, Jamali Brockett, first pounced on the victim when she was just 13 years old, raping her in a park. After that, a criminal indictment charges they sexually trafficked her for 8 years, taking every dollar she earned.

Brooklyn District Attorney, Charles Hynes, launched a Sex Trafficking Unit a year ago this month and said it's been enormously successful in prosecuting bad guys.

"In just one year, we have 26 sexual traffickers under indictment," Hynes said, "and not one of them has made bail.".

Hynes told reporters Damien Crooks and his cohorts threatened to harm the young woman's family, if she told anyone. In one incident, Hynes said Crooks and two men--the Brockett brothers--raped the victim on a rooftop, while her brother waited helplessly outside.

Lauren Hersh, Chief of the Sex Trafficking Unit, told us the girl's parents sensed something was wrong with their daughter. "The girl was sent by her parents repeatedly out of state, and when she came back, she was repeatedly threatened by Crooks," Hersh said. District Attorney Hynes added, "Crooks would not let her go."

Hynes told PIX 11 his office has reason to believe other girls were victimized, and he's urging them to come forward. The victim in this case told prosecutors Crooks and company once wanted her to recruit girls for prostitution at a party, and when she refused, she was beaten.

Professor Kern said a driving force in his student coming forward was fear that Crooks was going to target another member of her family for prostitution. The student's family has now been placed in protective custody by police and prosecutors.

Crooks turned himself in to the District Attorney's office, while Charles Hynes was announcing the indictment. Three other suspects are already in custody: Jawara Brockett, 33; Jamali Brockett, 31; and Darrell Dula, 24. Crooks is charged with sexual trafficking and rape. The other defendants face rape charges.

D.A. Hynes estimates that 100,000 American children are victimized every year by sexual traffickers. Anyone with information is asked to call the Sex Trafficking Unit's 24-hour hotline at (718) 250-2770.