Repeat Sex Offender Arrested Outside BK Synagogue: U.S. Attorney

WILLIAMSBURG, NY — A repeat sex offender accused of luring a teenager with gifts was arrested outside a Borough Park synagogue Wednesday evening, according to prosecutors.

Joseph Grunwald, of Williamsburg, stands accused of molesting a 14-year-old between April and June 2023 — the latest of a slew of similar crimes committed by the 31-year-old man, according to U.S. Attorney Breon Peace's office.

If convicted as charged, Grunwald could face a minimum 20-year-sentence, according to Peace.

And, given Grunwald lives near an elementary school and has worked as a school bus driver, Peace requested Gunwald's pretrial detention in a letter to Judge Taryn A. Merkl Thursday.

"[Gurnwald] is a danger to [the victim] and the community," Peace said in the letter. "The evidence shows that he has not only molested [the victim], but has also subsequently threatened him with physical violence and with disclosing private information, photos and videos, and has in fact distributed a photo of [the victim's] penis."

Grunwald first contacted the teenager via Telegram in April 2023 and offered the teen gifts including a cell phone to convince the teen to meet up and send nude photos, according to a criminal complaint.

In their conversations, Grunwald bragged about the other teenagers he had "sexually exploited," prosecutors contend.

"[W]ow, I like young boys," Grunwald told the teenager, according to the complaint.

Grunwald ultimately got the child alone in a car and molested him, prosecutors contend.

The attack was followed by relentless threats to the teen that Grunwald would physically harm him and tell his mother and young brother, according to Peace.

"You’re not the first boy I’ve done this to. I promise you that, and I’m warning you with your life,” the 31-year-old told the teenager, according to Peace.

A family member of the boy turned Grunwald in — but it's not the first time he's been caught, according to state records.

Grunwald was convicted in 2017 and again in 2018 related to sexual conduct with a 7- and 13-year-old, which both landed him on the state's sex offender registry.