Federal agents arrested Daniel Park for supplying explosive chemicals and aiding the California fertility clinic bomber.
They say Park collaborated with Guy Edward Bartkus, who died during the May 17 blast in Palm Springs.
The explosion caused major damage and shattered windows in nearby buildings.
Officials labelled the bombing as an act of terrorism.
Authorities say Park shipped ammonium nitrate to Bartkus before visiting him in Twentynine Palms, California.
Park allegedly spent two weeks testing explosives with Bartkus in his garage.
Agents arrested Park on Tuesday night at JFK Airport in New York after his extradition from Poland.
He had fled the U.S. four days after the bombing.
Park Amassed Explosives Over Several Years
The FBI says Park began purchasing ammonium nitrate online in October 2022.
He kept buying until May 2025, just days before the bombing.
In January, Park shipped 180 pounds of the chemical to Bartkus.
He later bought another 90 pounds and sent it directly to California.
Investigators searched Park’s home in Kent, Washington, and found a bomb recipe similar to the Oklahoma City attack.
Park made his first court appearance Wednesday in Brooklyn federal court.
FBI official Akil Davis confirmed Park’s role in sourcing explosives and assisting with the device tests.
Officials believe Park helped Bartkus refine the attack method during their time together.
Online Ideology Linked the Suspects
Park and Bartkus met through anti-natalist forums that oppose reproduction and population growth.
Davis said they shared a belief that people shouldn’t exist.
Court documents reveal Park frequently posted in an anti-natalist Reddit group for nearly a decade.
In 2016, he encouraged others to join what he described as a “hopeful” movement.
In March 2025, he tried to organize anti-natalist events in Washington but received no public replies.
Officials say Bartkus specifically targeted the American Reproductive Centres clinic.
The facility offers fertility services, including IVF and reproductive health evaluations.
Investigators say Bartkus attempted to livestream the explosion but failed.
They haven’t confirmed whether he meant to die in the attack or why he chose that specific location.
Global Authorities Respond as Investigation Unfolds
U.S. law enforcement worked with Polish authorities to capture and return Park.
The FBI believes the case reflects growing risks linked to ideological extremism online.
Agents continue examining Park’s digital footprint and forum activity.
Authorities expect more legal proceedings as the investigation expands.