The Department of Homeland Security's inspector general has turned the inquiry into the Secret Service deleted text messages into a criminal investigation, three sources familiar with the situation confirmed to ABC News Thursday.
The inspector general sent a letter to the Secret Service Wednesday night telling the agency to halt any internal investigations until the criminal probe has been wrapped up.
The inspector general's office told ABC News it doesn't comment on ongoing probes.
"Consistent with Attorney General guidelines, DHS OIG neither confirms nor denies information about our investigations," an OIG spokesperson said.
News of the probe came hours before the House Jan. 6 committee was set to hold a prime-time hearing at which it was expected the deleted texts would be addressed, amid questions about they could shed light on the actions of then-President Donald Trump.
It is unclear whether this criminal investigation would result in a referral to the Justice department but the inspector general wants the Secret Service to halt its internal review.
"The Secret Service is in receipt of the Department of Homeland Security Inspector General's letter," a Secret Service spokesperson told ABC News in a statement. "We have informed the January 6th Select Committee of the Inspector General's request and will conduct a thorough legal review to ensure we are fully cooperative with all oversight efforts and that they do not conflict with each other."
The Secret Service has said it has been cooperating with a House Jan. 6 committee subpoena and a National Archives and Records Administration inquiry, according to a source familiar with the situation.
The probe was first reported by NBC News.
The agency provided a single text exchange to the Department of Homeland Security inspector general investigating the agency's record-keeping, according to an agency letter to the House Jan. 6 committee obtained by ABC News on Wednesday, and the Jan. 6 committee suggested they broke federal records keeping laws.
"Four House committees had already sought these critical records from the Department of Homeland Security before the records were apparently lost," the committee said in statement. "Additionally, the procedure for preserving content prior to this purge appears to have been contrary to federal records retention requirements and may represent a possible violation of the Federal Records Act."
In December, the agency sent out communications to employees on how to upload digital files on their local devices if they are government records, according to a source familiar with the Secret Service migration process.
If the files were specific to the definition, employees were instructed to upload them prior to the migration, and the source said employees that did not do that, the content was likely lost when the phones were factory reset to implement the new wireless system. Individuals did not manually go on to the devices and delete content. That was done remotely by the agency, the source said.
There was also a second notification in early January advising employees prior to the start of the migration which occurred later in the month, the source said.