Indicted last May, Rock was accused of making two traffic stops on June 7, 2008, and securing cash in lieu of issuing a traffic citation.
That action constituted depriving individuals of their constitutional rights against unreasonable search and seizure.
Rock, 35, admitted his actions to the federal court and faces up to one year in prison and a $100,000 fine for each offense.
The government did not make a recommendation about his sentencing.
U.S. District Judge Sharion Aycock presided over the 22-minute hearing.
Rock was represented by Pontotoc attorney Brad Cornelison.
Aycock will not set a sentence date until completion of a report about Rock to guide her decision. It often takes several months for such a report.
She may order him to pay restitution.
Rock remains free on bond.
A 2008 complaint filed in Pontotoc County circuit court stated that Rock was performing his official duties for Ecru when, on two separate occasions, he stopped a vehicle driven by a Hispanic male, who did not have a valid driver’s license.
That complaint alleged Rock told the drivers that if they paid him the $140 fine, he would not arrest and take them to jail.
While state legal action generally must be taken within two or three years, a federal civil rights violation has a five-year deadline to secure an indictment.