Convicted killer Terry Speaks has told the judge, prosecutors and public defenders handling the trial of his alleged co-conspirator in the 2012 murder of Jaren Lockhart that he will refuse to testify if called.

Speaks, who is serving a life sentence at the Louisiana State Penitentiary at Angola, wrote a letter May 20 saying he has been informed by the Public Defenders Office that he will be called by prosecutors to testify against his ex-girlfriend, Margaret Sanchez.

In the letter filed with the 24th Judicial District Court, however, Speaks, said he will refuse to testify for either side in the upcoming murder trial.

“Please do not attempt by any measure or means to contact me or have me transported,” he wrote. “It will be a waste of all parties’ time that are involved. I wish to have nothing to do with this case.”

Sanchez’s trial is set for July 11 but could be delayed. Speaks has not been issued a subpoena to testify, and the Jefferson Parish District Attorney’s Office does not comment on its plans for open cases.

It’s not clear how Speaks could be compelled to testify if he doesn’t want to. He is already locked up for what amounts to two life sentences after being found guilty in June 2015.

During his trial and in hearings that preceded it, letters and recorded phone conversations showed Speaks became increasingly upset with Sanchez as he sat in jail and she remained free. Despite their earlier plans to get married, she began seeing someone else.

In one recorded conversation, Speaks mentioned the “spring cleaning” he did on her behalf. Prosecutors said that was a reference to cleaning up their home after the two of them stabbed Lockhart once through the heart one night in 2012.

Speaks also said during the conversation that he still had pairs of both women’s underwear, and he threatened to turn them over to the authorities.

Authorities say Sanchez and Speaks lured Lockhart from her job at a Bourbon Street strip club with the promise of money for sex, took her to their Kenner home and killed her. The three were caught on surveillance camera leaving the club that night, and Sanchez’s car was photographed entering Kenner.

The following evening, cameras photographed the car entering Mississippi and coming back about two hours later, a day before parts of Lockhart’s body began washing up on shore there.

Sanchez, 32, faces automatic life in prison if convicted.

Follow Chad Calder on Twitter, @Chad_Calder.