HUNTSVILLE, Texas » A Texas inmate facing execution for the fatal stabbing of a corrections officer more than 15 years ago is asking the U.S. Supreme Court to stop his lethal injection.

Attorneys for 35-year-old Robert Lynn Pruett had several appeals before the high court as Pruett’s scheduled Tuesday evening punishment approached.

Lawyers argue Pruett is innocent in the December 1999 death of corrections officer Daniel Nagle at the McConnell Unit prison in South Texas. Among the appeals is one that argues his punishment should be put off because attorneys anticipate likely advances in DNA testing would bolster their claim and allow examination of some evidence.

They contend that evidence now is too degraded to test because the state improperly stored it.

Pruett’s execution would be the seventh this year in Texas.