AKIPRESS.COM - Convicted serial killer Tommy Lynn Sells, who was sent to prison in 1999 and claimed responsibility for dozens of murders across the United States, was executed Thursday in Texas, media report.

Sells, 49, was convicted of killing 13-year-old Katy Harris while she slept in her Del Rio, Texas, home. Her murder landed Sells on death row, but he has been linked to at least 17 other killings and claims he has killed as dozens more.

Sells declined to make final remarks before his death, then took a few breaths, closed his eyes and began to snore as the lethal-injection drugs took effect, The Associated Press reported. He soon stopped moving and was pronounced dead 13 minutes later at 6:27 p.m. CT.

Sells' execution earlier had been halted when a district court ruled that the Texas prison system was required to disclose information about its lethal-injection drugs supplier and how the drugs are tested. But a federal appeals court on Wednesday threw out the ruling and reversed the decision.

Sells' attorneys made a plea to the U.S. Supreme Court to stay the serial killer's execution, but their plea was rejected Thursday.

In a statement to ABC News Thursday, Sells' attorneys said, "It is our belief that how we choose to execute prisoners reflects on us as a society. Without transparency about lethal injections, particularly the source and purity of drugs to be used, it is impossible to ensure that executions are humane and constitutional. It is our hope that the U.S. Supreme Court and the Texas courts will ultimately agree that we must have transparency about the execution process in order to ensure that prisoners are able to protect their Eighth Amendment rights."