Death row inmate Brandon Bernard has been killed by lethal injection at a federal prison after the US Supreme Court rejected a last-minute request to delay his execution.
Bernard, 40, was just 18 when he took part in the 1999 double murder of an Iowa religious couple, whose bodies he burned in the boot of their car in Texas.
He told Todd and Stacey Bagley’s family he was sorry shortly before he was put to death.
His execution is the first of five the Trump administration is rushing through in almost unprecedented fashion before incoming President-elect Joe Biden takes power, with the outgoing US leader having defied calls from campaigners including Kim Kardashian West to stop the killing.
It is the ninth execution since Attorney General William Barr resumed the use of the federal death penalty earlier this year following a 17-year hiatus.
The last time executions were carried out during a presidential lame-duck period was during the tenure of the 22nd president Grover Cleveland in the 1890s.
Defence lawyers had requested an emergency stay and argued in court that Bernard was a low-level member of a youth gang, while five jurors from his trial also pleaded for clemency, saying they regretted not opting for life in prison instead.
Reality TV star Kardashian West also voiced her concerns and was among those who had asked Mr Trump to stop the execution, saying in a series of recent tweets that Bernard’s “role was minor compared to that of the other teens involved”.
Kardashian West has met with Mr Trump during his time in office to discuss prison reform.
“I’m so messed up right now. They killed Brandon,” she tweeted after his death.
“He was such a reformed person. So hopeful and positive until the end. More importantly he is sorry, so sorry for the hurt and pain he has caused others.
“I could go on and on about what an amazing person Brandon was. I do know he left this earth feeling supported and loved and at peace.”
Kim Kardashian West speaks alongside Donald Trump during a criminal justice reform event in 2019
One of Bernard’s co-defendants, Christopher Vialva, was put to death in September.
Several more inmates are set to be executed before Mr Biden takes office on 20 January.
Alfred Bourgeois is scheduled to be executed later today for torturing and killing his two-year-old daughter in South Texas in 2004.