Staffer of New York Mayor Bill de Blasio, Arrested for Child Pornography

A leading young Democrat and de Blasio administration employee has a secret taste for sickening kiddie porn that involves baby girls as young as 6 months old, court papers revealed Friday.

Jacob Schwartz, 29, was busted for allegedly keeping more than 3,000 disgusting images and 89 videos on a laptop after downloading the filth from the internet.

The illegal smut shows “young nude females between the approximate ages of 6 months and 16, engaging in sexual conduct… on an adult male,” court papers say.

Schwartz’s father — labor lawyer and Democratic insider Arthur Schwartz — called his son’s case “a personal tragedy.”

“I understand these are serious charges,” said the elder Schwartz, who watched his son get arraigned in Manhattan Criminal Court on Thursday night.

“He’s already in therapy for this.”

Jacob Schwartz surrendered to NYPD computer-crimes investigators in Manhattan’s 13th Precinct on Thursday morning, sources said.

He’d been under investigation since March 29, when he handed over his laptop and gave cops written permission to search it, court papers say.

Jacob Schwartz is the president of the Manhattan Young Democrats and the downstate region vice president of the New York State Young Democrats.

But his name and photo were scrubbed from both groups’ Web sites after The Post broke the news of his arrest.

A statement from the Manhattan Young Democrats said the organization was “shocked” by the allegations against Schwartz, and added that he was “no longer a member of the board, and an interim president is now in place.”

A photo posted last year on Twitter shows him posing with Robby Mook, then the campaign manager for Hillary Clinton’s disastrous presidential campaign.

Schwartz is employed as a $66,360-a-year computer programmer analyst in the city Department of Design and Construction, where he works on the “Build It Back” Hurricane Sandy recovery and resiliency program.

Schwartz was hired after working there as an intern in fiscal 2015, records show.

De Blasio ignored questions about his arrest following a news conference in The Bronx, but a spokeswoman later said Schwartz “is being terminated immediately, and the agency is cooperating with investigators.”

According to his online biography, Schwartz got involved in politics at a young age, helping his father campaign for Democratic district leader in Greenwich Village.

The elder Schwartz served as New York counsel to Vermont Sen. Bernie Sanders’ failed presidential campaign, and was also the campaign treasurer for law professor and liberal activist Zephyr Teachout when she challenged Gov. Andrew Cuomo for the 2014 Democratic nomination.

Arthur Schwartz also had his own brush with the law in 2015, when he was busted for removing hidden surveillance cameras trained on the front door of a $700-a-month, rent-stabilized apartment occupied by a 93-year-old client battling her landlord.

Prosecutors agreed to drop felony grand larceny charges in exchange for Arthur Schwartz paying $720 in restitution.

Jacob Schwartz attended Lehigh University, where he was a member of the “On Tap” a capella singing group, which later scored a gig on the Celebrity Infinity cruise ship.

The all-male quartet scored high marks on the “Cruise Critic” website, where a member from Denmark wrote in 2013, “we really enjoyed the On Tap boys on our Infinity cruise to Alaska.”

Jacob Schwartz was charged with promoting a sexual performance by a child and possessing a sexual performance by a child under 16, both felonies, and released on $7,500 bail.