The Florida man who mailed pipe bombs to critics of President Donald Trump said in a letter to a federal judge that attending a Trump rally "became like a new found drug," according to documents released Tuesday.

Cesar Sayoc, 57, who pleaded guilty to explosives charges last month, claimed in a series of letters that he has abused steroids for over 40 years. The letters were posted in his court case file.

His lawyers say they will cite Sayoc's extensive steroid use at his August sentencing and have asked the court not to conduct a psychological exam.

In the handwritten letters filed in the U.S. District Court for the Southern District of New York, Sayoc told U.S. District Judge Jed S. Rakoff that "politics is dirty, ruthless, deadly." He wrote, "I wished it had never come along into my life."

'Extremely sorry':Pipe bomb suspect Cesar Sayoc pleads guilty in spree aimed at Trump critics, including Obama, Biden

Pipe bomb suspect:'Devices were not ever meant to work ... hurt or harm'

He faces a mandatory 10-year prison term and up to life at his sentencing, scheduled for Aug. 5.

Sayoc, who described a Make America Great Again rally as fun, also wrote he "was on the front lines of war between right & left" at a rally in Chicago. He is linked to Twitter accounts vilifying Democrats, including liberal donor George Soros, to whom he mailed one of the bombs. Sayoc also drove a van covered in pro-Trump and anti-Democrat stickers.

He previously said he never intended to hurt anyone when he mailed 16 pipe bombs to CNN and top Democrats, including former Democratic presidential nominee Hillary Clinton and ex-President Barack Obama. Investigators found and disabled the devices, resulting in no injuries.

In a letter filed earlier this month, Sayoc wrote "extreme emotional circumstances" in court influenced his answer when a judge asked if he knew the explosive devices would cause harm.

Contributing: The Associated Press