Oscar Ray Bolin, 53, was executed at Florida State Prison in Starke on Thursday night. Bolin, a former carnival worker, was convicted of killing three Tampa Bay-area women. Governor Rick Scott signed a death warrant for Bolin in October for the 1986 killing of Teri Lynn Matthews, 26.

Bolin’s execution, scheduled for 6 p.m., was delayed for more than four hours as the US Supreme Court considered Bolin’s final appeal. The justices denied the appeal just before 10 p.m.

Thirty-six people witnessed the execution. At 10:05, prison authorities began the lethal injection of the chemicals midazolam hydrochloride, vecuronium bromide and potassium chloride. Bolin’s eyes closed, and his mouth fell wide open about a minute later.

When a prison official shook him by the shoulders at 10:09 there was no response. His breathing then grew more labored and he appeared to stop breathing by 10:13 p.m. A doctor entered the execution chamber at 10:15 p.m. Governor Scott’s office said Bolin was pronounced dead at 10:16 p.m.

Bolin had also received a death sentence for the killing of 17-year-old Stephanie Collins and 25-year-old Natalie Holley. A death warrant was never signed for the Collins case. The verdict in Holley’s case was thrown out for legal reasons, but Bolin was eventually found guilty of second-degree murder in that case. All three victims were stabbed. Relatives of Matthews and Collins were present for Bolin’s execution.

On Wednesday, Bolin told a local television station that he was innocent of the three stabbing murders. “I didn’t know ’em, never seen ’em, never met’ em,” he said. He told Fox 13 TV that evidence used to convict him was both tampered with and planted.

During Bolin’s trial for the murder of Matthews, Bolin’s younger half-brother said he witnessed Bolin beating Matthews and trying to drown her with a garden hose. The half-brother later recanted his testimony, and then reversed his story yet again.

“My conscience is clear,” Bolin said the day before his execution. “I’m at peace with myself. It’s my release. My punishment’s over. After 28 years of this, being in this box for 28 years, it’s a release. … They can’t hurt me no more.”

While on trial, Bolin and a member of his defense team fell in love. Rosalie Martinez, a paralegal at the Hillsborough Public Defender’s office who was married to a prominent Tampa attorney, divorced her husband and married Bolin on live television in 1996. Rosalie Bolin maintained her husband’s innocence in Matthews’ killing and she is now one of Florida’s most outspoken death penalty opponents.

The three Tampa-area killings went unsolved until an anonymous tip came into authorities in 1990. They would later find out the tip came from the new husband of Bolin’s ex-wife. The ex-wife reportedly told her new mate that Bolin had admitted to the 1986 killings.

Bolin was already serving a 22- to 77-year prison sentence in Ohio for the kidnapping and rape of a 20-year-old waitress in Toledo in 1987. When he was brought back to Florida, a task force attempted to connect him to slayings in 26 states, but he was officially linked to just one other, the 1987 strangulation of Deborah Stowe, 30, in Greenville, Texas. Texas prosecutors declined to seek an indictment in that case.

Bolin’s execution was the first in the US in the new year. Eight more are scheduled through the end of 2016. There were 28 executions nationwide in 2015, the lowest number since 1991, according to the Death Penalty Information Center. Twenty-four of these executions took place in just three states: Texas (13), Missouri (6) and Georgia (5).

Many states have stayed death sentences due to the inability to obtain the chemicals to be used in lethal injections, as sources in both the US and Europe have stopped making them available. Ohio carried out no executions in 2015 and only one in 2014, due to a shortage of lethal-injection drugs, and has delayed all executions until 2017. The state, however, has 11 executions scheduled in 2017, eight in 2018 and six in 2019.

Since the US Supreme Court reinstated the death penalty in 1976, there have been 1,423 executions across the US. The condemned have included those convicted of crimes as juveniles, foreign nationals denied their consular rights and the mentally impaired.

The barbaric practice continues despite its condemnation by the European Union and the vast majority of industrialized nations. Thirty-one of the 50 US states, in addition to the US government and military, have capital punishment on the books.