An ex-girlfriend of Brock Turner, the Stanford University swimmer convicted of sexually assaulting an unconscious woman, called him her "dearest friend" in a letter submitted to the court for his trial, newly released court documents showed on Tuesday.

"He never once pressured me into any situation or decision that I didn't feel true to myself in," the ex-girlfriend, Lydia Pocisk, wrote in the letter obtained by the San Francisco Chronicle.

Posick wrote that Turner was dedicated to his swimming, and that people shouldn't hold his calm nature against him.

"It has been said that due to his calm demeanor, he did not care that this was happening to him, that he intentionally did this, which is simply not the case, he is just very good at being and seeming relaxed."

Posick wrote that they met in middle school and dated during their junior and senior years of high school.

The judge ultimately sentenced Turner to six months in jail for sexually assaulting a young woman passed out from drinking too much at a fraternity party where they had met in January of 2015. Turner is scheduled to be released from Santa Clara County jail in September after completing three months of his sentence due to good behavior.

The judge, Aaron Persky, has endured widespread criticism and calls for his removal from the bench. On Tuesday, Santa Clara County District Attorney Jeff Rosen used a prosecutor's authority to disqualify the judge to block transfer of a new sexual assault case involving a former nurse in San Jose.

In a separate letter to the judge, Turner's mother, Carleen, wrote that prison would damage her son "forever." She described any potential jail time as a "death sentence."

The prosecutor's so-called "papering" of Persky came days after several potential jurors told the judge they couldn't serve on a jury in his courtroom because of the Turner sentence. The prosecutor removed Persky from the new sexual assault case the day after he tossed out a misdemeanor theft trial before it reached the jury. Perky ruled on Monday that prosecutors had not proven their theft case during the two-day trial and dismissed the case and the jury before deliberations started.

"We are disappointed and puzzled at Judge Persky's unusual decision to unilaterally dismiss a case before the jury could deliberate," the district attorney said in a prepared statement. "After this and the recent turn of events, we lack confidence that Judge Persky can fairly participate in this upcoming hearing in which a male nurse sexually assaulted an anesthetized female patient."

The district attorney said he hasn't decided whether he will disqualify Persky from all new sexual assault cases that may get assigned to him in the future.

Persky didn't respond to requests for comment.

The Associated Press contributed to this report.