OAKLAND (CBS SF) – An Oakland man was sentenced to federal prison after being convicted in a sexual extortion scheme targeting teens on Instagram, federal prosecutors say.

Acting U.S. Attorney Stephanie Hinds’ office announced Thursday that 22-year-old Delaney Tang was sentenced to 60 months after pleading guilty to solicitation of child pornography and conspiracy to commit cyberstalking earlier this year. A co-defendant in the case, 21-year-old Vincenz Sison of Concord, has also pleaded guilty to conspiracy.

READ MORE: UPDATE: Crews Make Progress in Big Sur Firefight; Containment at 35 Percent

The pair were arrested last year following an investigation by the San Francisco Police Department’s Internet Crimes Against Children Unit.

Police said they launched their investigation after an official at a high school in San Francisco reported that several students were extorted for sexually explicit videos and pictures on social media.

During their investigation, police determined that Tang had created dozens of social media accounts on various platforms under false names and false profile photos, in some cases posing as a minor.

Sison was used by Tang to contact and harass some of the victims, police said. Victims in the Bay Area, Northern California and Utah were identified by SFPD.

“Some of the victims were harassed and tormented for months,” San Francisco Police said at the time.

READ MORE: Big Sur Residents Told to Boil Water Due to Possible Wildfire Damage to Utility

According to the plea agreement, Tang admitted that he used Instagram to harass, threaten and extort a 12-year-old girl into sending him nude photos and videos of herself. He also admitted attempting to coerce the girl to film herself in sex acts with an underage male, with the assistance of Sison.

Prosecutors said when the teen stopped responding to Tang’s messages, he then posted videos and photos of the victim on Instagram and other sites.

Tang also admitted using Instagram to extort additional young victims, seven of which were between the ages of 11 and 14.

Along with the prison term, Tang was sentenced to an eight-year period of supervised release.

Prosecutors said Tang is next scheduled to appear in court January 12 to determine restitution for his victims. He is expected to surrender to authorities and begin serving his sentence on January 19.

MORE NEWS: Hazardous Sneaker Waves Threaten San Francisco Beachcombers

Sison will be sentenced in February.