June 24 (UPI) -- Daniel Jongyon Park, the Washington state man charged with providing explosive materials to a suicide bomber who attacked a California fertility clinic last month, died Tuesday while in federal custody. Park, 32, was found unresponsive inside his cell around 7:30 a.m. PDT, at the Metropolitan Detention Center in Los Angeles, where jail staff immediately began life-saving measures, the Bureau of Prisons announced in a statement. He was pronounced dead after being transported to a local hospital. The Federal Bureau of Investigation and U.S. Marshals Service are investigating Park's death. No details have been released and a cause of death has not been determined. Park, of Kent, Wash., was the alleged accomplice of Palm Springs bomber Guy Edward Bartkus, who detonated a vehicle bomb outside the American Reproductive Centers on May 17. Several people were injured and Bartkus was killed. After the attack, Park traveled to Poland before being deported back to the United States. He was arrested on June 4 after arriving on a flight to John F. Kennedy International Airport in New York, and was moved to the Los Angeles detention center on June 13. Earlier this month, Attorney General Pam Bondi thanked the Polish government for returning Park to the United States to face charges. "Bringing chaos and violence to a facility that exists to help women and mothers is a particularly cruel, disgusting crime that strikes at the very heart of our shared humanity," she said. Park was indicted for alleged malicious destruction of property and charged with supplying Bartkus with 180 pounds of ammonium nitrate, a chemical compound used in explosives. Bartkus was allegedly motivated by anti-natalist views that people should not be born without their consent. According to the Justice Department, Park shared the same beliefs.