A law enforcement source familiar with the investigation but not authorized to speak publicly told The Associated Press the subpoenas went out Thursday.
The subpoenas seek documents relating to abuse allegations, payments to victims or findings from internal church investigations.
Underwood’s office is pursuing a civil investigation into the church’s response to abuse reports and has also reached out to local prosecutors authorized to convene grand juries or pursue criminal investigations.
Church officials say they will cooperate.
The announcement comes three weeks after a grand jury investigation found rampant sexual abuse of more than 1,000 children by about 300 priests in Pennsylvania.