A Jan. 6 rioter who was pardoned by President Trump and released from prison last week is being sought on preexisting charges in Texas of soliciting a minor online.

The district attorney in Harris County, Texas, said on Tuesday that his office was searching for Andrew Taake, who at the time of the Capitol riot was awaiting trial on charges brought in 2016 of using a messaging app to pursue a sexual relationship with a 17-year-old.

A few months after the attack at the Capitol, he told a woman on the dating app Bumble that he had been involved in the riot, and she turned him in to the F.B.I.

Mr. Taake, 36, later pleaded guilty to attacking police officers outside the Capitol with bear spray and a metal whip and was sentenced in June to more than six years in prison. He was freed from federal prison in Colorado last week, not long after Mr. Trump issued a sweeping grant of clemency to all of the nearly 1,600 people charged in connection with the storming of the Capitol.

The man’s release took place despite the fact that the district attorney’s office had sent prison officials a copy of the open warrant for Mr. Taake’s arrest in Harris County five days before his pardon was issued.

Sean Teare, the district attorney, said in a statement that his office was currently searching for Mr. Taake to make him face the charges of solicitation of a minor.