Prosecutors in the Aaron Hernandez murder trial have said that an anonymous tipster, who claimed a juror was “untruthful,” had a sexual relationship with the former New England Patriots star.

Four months after Hernandez was found guilty of the murder of Odin Lloyd, prosecutors filed court papers on Monday alleging that the athlete had a “sexually explicit relationship” with a tipster.

Hernandez’s lawyers said the tipster, who is only identified as “Katy,” called them and alleged that one of the jurors knew the defendant had been charged with murdering two men in 2012. Selected jurors were not supposed to have any knowledge of that case as it is a separate trial. Prosecutors, however, have responded claiming that Katy and Hernandez had a sexual relationship and she made up the story to get him a new trial.

“It was a relationship that [the tipster], based on her uninformed belief in the defendants’ innocence, hoped would continue after the defendant’s release,” prosecutors said.

The state also said in the filing that Katy wrote letters that were sexual in nature to the former NFL star while he was incarcerated.

The Associated Press noted that the filing came one day after Hernandez’s fiancée, Shayanna Jenkins, petitioned to a Rhode Island court that the surname Hernandez be added to hers.

Hernandez was found guilty of first degree murder in April and sentenced to life in prison.

For more sports news follow Michelle on Twitter @PhilaMichelle