FLORIDA, United States (AFP) — A 64-year-old man was put to death by lethal injection in Florida on Tuesday for the 1990 murders of his employers, the 34th execution in the United States this year.

Victor Jones was executed at 6:13 pm (2213 GMT) at a state prison near Jacksonville, the Florida Department of Corrections said on its website.

Jones stabbed Jacob Nestor, 67, and Matilda Nestor, 66, to death during a robbery just days after beginning work at their Miami company.

Before dying of his wounds, Jacob Nestor managed to shoot Jones in the head.

The Florida Supreme Court declined last week to halt Jones’s execution after hearing arguments that he was intellectually disabled and suffered abuse at an infamous reform school while a teenager.

There have been 34 executions in the United States this year, the most since 2014, when 35 inmates were put to death.

Florida has carried out the most executions — 13 — followed by Texas with five and South Carolina and Alabama with four.

Twenty-eight of this year’s executions have been carried out by lethal injection, two by firing squad and four by nitrogen hypoxia, which involves pumping nitrogen gas into a face mask, causing the prisoner to suffocate.

The use of nitrogen gas as a method of capital punishment has been denounced by United Nations experts as cruel and inhumane.

The death penalty has been abolished in 23 of the 50 US states, while three others — California, Oregon and Pennsylvania — have moratoriums in place.

President Donald Trump is a proponent of capital punishment and on his first day in office, called for an expansion of its use “for the vilest crimes.”