A Texas inmate convicted of the death of a prison guard has been executed after the US Supreme Court rejected his lawyer's attempts to halt the punishment.
Robert Pruett was given a lethal injection on Thursday evening for the December 1999 death of corrections officer Daniel Nagle at a prison southeast of San Antonio.
Mr Nagle was repeatedly stabbed with a tape-wrapped metal rod, though an autopsy showed he died from a heart attack that the assault caused.
Prosecutors have said the attack stemmed from a dispute over a peanut butter sandwich that Pruett wanted to take into a recreation yard against prison rules.
The 38-year-old Pruett was already serving a 99-year sentence for a neighbour's killing near Houston when he was convicted in Mr Nagle's death.
Pruett's execution is the sixth this year in Texas.