Attorneys for convicted killer Terry Speaks are asking for a new trial, pointing to a belated letter from an inmate who says one of three other prisoners who testified that Speaks confessed to the crime in a New York jail cell changed his story and got details for his testimony from his father, who was getting information from the Internet.

The letter, according to a filing Thursday by John Benz, of the Jefferson Parish Public Defenders Office, was dated and postmarked June 10, five days before Speaks’ trial began, but it was sent to the Orleans Parish office and wasn’t delivered to Speaks’ attorneys until after Speaks was convicted in a Jefferson Parish courtroom of killing and dismembering Bourbon Street dancer Jaren Lockhart. He was sentenced to life in prison.

Benz wrote that the chief of trials for the Orleans office said errors in the letter prevented his staff from realizing it was related to the Speaks trial, delaying its delivery.

Benz said the letter “reveals certain information that would have been crucial to the examination of at least one of the state’s main witnesses in the matter, Trevor Lucas.”

The letter was written by Elijah Sanford, an inmate in Otisville, New York, who says he is a paralegal and spoke at length with Lucas.

Lucas is one of three inmates who testified during the June trial that Speaks told them he killed Lockhart in 2012 with the help of his girlfriend, Margaret Sanchez, who has yet to be tried.

Sanford’s letter says Lucas told him he changed the facts in his story so they would be consistent with those given to him by investigators who questioned him before Speaks’ indictment. It also says Lucas was getting information from the Internet via his father.

Sanford also wrote that Lucas once offered him $100,000 to have one of Sanford’s family members “set someone up” for Lucas, though it is not clear what that meant.

Benz said that because the evidence in the case against Speaks was circumstantial — there was no murder weapon, forensic evidence or eyewitness to the killing — the potential discrediting of one of the former inmates would have been significant.

Sanford claims in his letter that Lucas’ testimony also isn’t credible because he has a verbal agreement to have his sentence reduced in return for testifying.

“Whether the accused committed the horrific acts charged is of no consequence to me,” Sanford wrote. “What is of absolute consequence, is that the accused (sic) constitutional rights be preserved, protected and defended at all cost. At the writing of this letter, he is not receiving such and his attorneys are not aware of the information I have thus far provided. I have more information regarding this matter, but will (sic) reserving it.”

Benz wrote that Sanford is willing to testify to support the allegations in his letter.

Speaks’ previous requests for a new trial — due to media coverage and his short-lived decision to represent himself — were denied by 24th Judicial District Judge Stephen Grefer.

Speaks is appealing his convictions on charges of second-degree murder, obstruction of justice and conspiracy to obstruct justice.

Sanchez, who faces the same charges, is scheduled to go to trial in December.