Man Charged With 3D-Printed Gun, Assault Firearm And Attempted Online Contact With Minor

Authorities said a South Amboy resident allegedly exchanged sexual messages with an undercover officer posing as a teen and later was found with unregistered weapons and large-capacity magazines during a Feb. 6 search.

A Middlesex County man has been charged with multiple weapons offenses and attempted crimes involving sexual communications with someone he believed was a minor, Acting Attorney General Jennifer Davenport and the state Division of Criminal Justice said.

Oskar Smieszek, 23, of South Amboy, is charged by complaint with second-degree manufacturing an unregistered, unlicensed firearm with a three-dimensional printer; second-degree possession of an unlicensed, unregistered assault firearm; fourth-degree possession of large-capacity ammunition magazines; third-degree attempted impairing the morals of a child; and third-degree attempting to show obscene material to a child, authorities said.

“The charges announced today reflect two major areas of enforcement of our office – protecting children from sexual predators and protecting everyone from gun violence,” said Acting Attorney General Davenport. “So-called ‘ghost’ guns that are made with 3D printers are untraceable, but no less deadly than other weapons. And anyone who tries to use the anonymity of social media sites to prey on children should understand that they will be held accountable.”

What authorities allege

According to documents filed in the case, an undercover law enforcement officer posing as an underage girl on a social media platform received a message in April 2025 from a user later identified as Smieszek. Authorities said Smieszek had sexual conversations and discussed meeting the person he believed was underage.

A search warrant executed at Smieszek’s residence on Feb. 6, 2026, led investigators to seize multiple digital devices as well as weapons and magazines, authorities said.

“We discovered this defendant, and his illegal weapons, as he allegedly attempted to arrange a sexual encounter with someone he believed was a child,” said DCJ Director Theresa L. Hilton.

Evidence seized

Authorities said officers recovered:

• Two unregistered firearms

• One 17-round magazine

• Three 30-round magazines

• Three 20-round magazines

The search also produced images taken at the residence, authorities said.

Penalties

Authorities said second-degree charges carry a sentence of five to 10 years in state prison and a fine of up to $150,000. Third-degree charges carry three to five years in prison and a fine of up to $15,000. Fourth-degree offenses carry up to 18 months in state prison and a fine of up to $10,000.

“The charges in this case address two grave threats to public safety: illegal firearms and sexual predators,” said Lieutenant Colonel David Sierotowicz, Acting Superintendent of the New Jersey State Police. 

Davenport credited the New Jersey State Police with investigating the case. The matter is being prosecuted by Deputy Attorney General John Donovan of the Division of Criminal Justice, authorities said.