A man who was accused of supplying chemicals to make bombs targeting a California fertility clinic died in custody, federal officials said on Tuesday.

Daniel Park was arrested earlier this month at John F. Kennedy International Airport in New York upon returning to the United States after being deported from Poland.

Recommended Stories

• California man arrested in attempt to help Islamic State as Trump warns of terrorist sleeper cells
• ICE says it arrested 11 Iranian illegal immigrants as Trump warns of sleeper cells in US
• Mexican man pleads guilty after being allegedly aided by arrested Wisconsin judge

The Federal Bureau of Prisons said on Tuesday morning, “At approximately 7:30 a.m., Daniel Park was found unresponsive at the Metropolitan Detention Center (MDC) in Los Angeles, California.”

It noted that life-saving measures were conducted by responding employees, but Park was pronounced dead at the hospital. No cause of death was provided.

Prosecutors accused Park of shipping 180 pounds of ammonium nitrate to Guy Bartkus, the suspect behind the explosion, ahead of the May bombing. U.S. Attorney Bill Essayli said days before the explosion, Park ordered another 90 pounds of ammonium that was shipped to Bartkus.

Prosecutors said the two men planned the attack for more than a year.

Days after the bombing, Park bought a plane ticket in cash and flew to Poland, according to Vincent Chiappini, a federal prosecutor with the U.S. attorney’s office for New York’s Eastern District.

Park attempted to harm himself when Polish authorities made contact to detain him. He was then deported back to the U.S., officials said.

SUSPECT IN EXPLOSION OUTSIDE CALIFORNIA FERTILITY CLINIC KILLED IN ATTACK

Bartkus, who was behind the actual explosion, died as a result of the bomb. He was believed to be supportive of antinatalist ideology, a belief system that opposes human reproduction.

No clinic employees were injured, and the facility’s laboratory, including stored eggs and embryos, was left intact.