Silambarasan, Manikandan and Vignesh were involved in a number of dacoity and robbery cases in the city and a total of nine cases were pending against them, a police release said.
The trio had recently hurled country bombs at the entrance of the district court complex.
In this background, Police Commissioner Sumit Sharan issued orders detaining the three under the Goondas Act.
The detention orders were served on them in the prison, the release added.