According to reports by ABC and CNN, the US Secret Service has turned over a list of agency-issued cell phone numbers.
ABC reported that the move to release agents' numbers will allow investigators to determine which officers' records they want to review as part of their investigation.
James Murray is delaying his retirement to make sure the agency cooperates with investigators.
"I feel strongly about using this time to ensure our agency's continued cooperation, responsiveness, and full support with respect to ongoing Congressional and other inquiries," Murray told his workforce in a message.
The agency was criticized for the deletion of text messages from agents' phones that could have been used as evidence.
The inspector general of the Secret Service obtained a list of personal cell phone numbers for agents as part of an investigation into the attack on the Capitol.
Deleting agents' text messages may have violated federal record-keeping laws.
The independent watchdog that oversees the Department of Homeland Security has been accused of covering up the missing messages.
"We are writing with grave new concerns over your lack of transparency and independence, which seem to be jeopardizing the integrity of a crucial investigation run by your office," the lawmakers wrote in an open letter to the inspector general.
Cuffari should be removed from oversight of the investigation because his delayed disclosure to Congress about the deleted Secret Service records casts serious doubt on his ability to conduct such an important investigation.