The Office of the Special Counsel deleted text messages from the iPhone of fired FBI agent Peter Strzok before turning it over to the Department of Justice Office of the Inspector General (OIG), according to a report released by the federal watchdog.

On Thursday, the Justice Department’s inspector general released a report stating thousands of text messages exchanged between Strzok and FBI attorney Lisa Page could not be recovered after Mueller’s team wiped clean the phones it had issued them.

So Mueller's team wiped ALL of the data off of Peter Strzok's iPhone after determining "it contained no substantive text messages." Given what we know about Strzok, this smells like quite the coverup. Time for Congress to step in?https://t.co/mOgpBbDVO4 pic.twitter.com/9w2mEPK64C — Jordan Schachtel (@JordanSchachtel) December 13, 2018

“SCO’s Records Officer told the OIG that as part of the office’s records retention procedure, the officer reviewed Strzok’s DOJ issued iPhone after he returned it to the SCO and determined it contained no substantive text messages,” the watchdog report reads. As Conservative Review national security reporter Jordan Schachtel first discovered, the OIG said Strzok’s cell phone was “reset to factory settings,” deleting all data stored on the device.

The federal watchdog said in the report it found “no discernible patterns” about the content of thousands of messages the FBI was able to recover between Strzok and Page. Both have been part of Mueller’s investigation of possible collusion between the Trump campaign and Russia.

Strzok and Page testified before Congress this summer, and the former FBI agent admitted that he had not turned over all of his communications with Page to the Inspector General from his personal phone, even though their recovered conversations showed the two suggesting they move to apps like iMessage or Gmail. Strzok told outgoing Rep. Darrell Issa (R-CA) that it is a “safe assumption” that he sent messages to Page from his personal phone that were similar in nature to the widely-publicized messages attacking Trump supporters. He told House Judiciary Chairman Bob Goodlatte (R-VA) that he himself determined which messages on that phone were “relevant to FBI business” that the Inspector General could review.

At that time of their exchanges, the FBI was investigating whether former secretary of state and then-presidential candidate Hillary Clinton improperly used a private email account while she was Secretary of State. Strzok, a senior counterintelligence agent, was assigned to the case, as was Page. Reports claimed the two were romantically involved during this time. Strzok was ultimately fired after anti-Trump text messages between him and Page were discovered by the special counsel.

Thursday’s report said the FBI used special software to collect more than 20,000 text messages from the pair’s phones, but not all were sent between Strzok and Page. Investigators have already released some of the controversial texts, including a message from Strzok saying he would “stop” President Donald Trump from winning the election.

Missing text messages from the pair’s iPhones, though, continue to elude the FBI.

Early this year, the Office of the Inspector General contacted Verizon Wireless to determine if the carrier retains old text messages. Verizon said messages are retained for up to seven days after they are sent, and then erased. The missing messages in question were much older than a week by that time and Verizon no longer had them.

The United International Press contributed to this report.