New Jersey ? Drawings found in the prison cell of a man suspected of plotting to attack Fort Dix suggest that he wants to seek revenge against FBI agents and should remain in custody, prosecutors said Monday.

The drawings – include one with the letters “FBI” and a gun pointing to them – are another reason that Agron Abdullahu should not be released from custody as he awaits trial, the U.S. Attorney’s Office said in legal documents filed Monday.

Abdullahu seemed to be thinking about “seeking revenge against the FBI agents who caused him to be imprisoned in the first place,” they wrote. “Releasing Abdullahu now would not only endanger the community at large, but also the agents who investigated this case.”

Guards at the Federal Detention Center in Philadelphia found the FBI drawing and another in the one-person cell where Abdullahu is being held.

The government said the drawings were etched with the screw from a light switch plate onto the door of Abdullahu’s cell.