Despite maintaining his innocence for three decades and a last-ditch effort to have the court reconsider, Texas inmate Lester Bower, who had been sitting on death row for 30 years, was executed on Wednesday.

A prison official stated the specifics of the execution, saying that Bower was pronounced dead at 6:36 p.m. after being given a lethal injection at the state's death chamber in Huntsville, Texas, according to Reuters.

During his incarceration, Bower became the state's oldest death row inmate. He was a former chemical salesman who was convicted of killing four people in October 1983 after a botched deal on a $4,000 ultralight airplane.

Prosecutors said that Bower murdered Bob Tate, a contractor, in order to steal an airplane Tate was selling. Police officer Ronald Mayes, sheriff deputy Philip Good and interior designer Jerry Brown were also killed, reported the Arlington Star-Telegram.

Airplane parts supposedly belonging to Tate's aircraft were found in Bower's residence. Phone records also showed that Bower had contacted Tate previously. However, no incriminating fingerprints were found at the crime scene and a murder weapon was never recovered, according to Reuters.

There were also no witnesses to the crime.

Bower maintained his innocence. "I did not," he said when asked if he committed the crime he was convicted for.

"What's more, I feel we have had a reasonable number of people come forward with credible stories to say I did not commit these murders," he added.

Four witnesses previously implicated a gang of Oklahoma drug dealers in the slayings. One of them supposedly told his girlfriend that the killings were the result of a drug deal gone wrong, reported the Arlington Star-Telegram.

Judge James Fallon acknowledged the plight of Bower's case, but still denied the inmate's request for a new trial.

"While the new evidence produced by the defendant could conceivably have produced a different result at trial, it does not prove by clear and convincing evidence that the defendant is actually innocent," Fallon wrote.

Bower leaves behind two daughters, both of whom have started families of their own during his time in jail. His wife, Shari, divorced him and remarried during this time.

Prior to the execution, Bower addressed his plight, as well as the people who became part of it, reported Reuters.

"Much has been written about this case, not all of it has been the truth. But the time is over and now it is time to move on. I want to thank my attorneys for all that they have done," he said. "They have afforded me the last quarter of a century."