An appeals court has upheld the double murder conviction of a man accused of killing an elderly Eunice couple in 2006, a case unsolved for nearly six years before a cold-case team cracked it in 2011.

Warren Ray “Boo Boo” Gautreaux is serving a life sentence after a jury convicted him last year on two counts of first-degree murder in the deaths of Youric Courville, 83, and his wife, Mary Ann Courville, 70.

In an opinion released Wednesday, the state 3rd Circuit Court of Appeal denied Gautreaux’s bid to strike the verdict.

Gautreaux had argued the prosecution’s case relied on improper hearsay testimony and that his defense attorney was not given enough leeway to question state witnesses about whether they made deals with prosecutors in exchange for light treatment on pending criminal charges.

The three-judge appeals panel ruled the use of the hearsay evidence, even “if considered partially improper,” was not enough to cast doubt on the convictions and that there was no evidence any witness had made a deal with prosecutors.

“In order to obtain a new trial, the defendant must show that an injustice has been done, and Mr. Gautreaux has failed to do so in this case,” the appeals judges wrote.

The killing was among the more notorious in St. Landry Parish in recent years.

A neighbor found the Courvilles dead in their home on Boudreaux Street early Jan. 10, 2006.

Both died from knife wounds.

Gautreaux was long considered a suspect, but he was not arrested in the case until 2011, when a task force of several local law enforcement agencies came together to re-examine the case, resubmit evidence and track down new witnesses.

The prosecution relied heavily on the testimony of witnesses who said they either heard Gautreaux confess to the killings or heard him discuss plans to rob the couple of cash and prescription drugs.