Texas executed the state's oldest death row inmate Lester Bower, who was convicted of killing four men in 1983, on 3 June. Bower, who served 30 years on death row, maintained he was wrongly convicted and attempted until his death to stop his capital punishment.

According to Reuters, Bower was executed by lethal injection at the state's death chamber in Huntsville and pronounced dead at 6.36pm CDT. CBS News reported that as the lethal dose of pentobarbital took effect, Bower snored softly around six times before he stopped moving.

Hours before his execution, the US Supreme Court rejected a last minute appeal by his lawyers. Reuters reported he had previously faced imminent execution six times.

"This is not a typical death penalty case," Bower's lawyer Peter Buscemi appealed to the justices. However, an assistant Texas attorney general, Stephen Hoffman, said that 30 years of litigation was enough for the families of the victims.

In his last statement, Bower allegedly said: "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. They have afforded me the last quarter of a century".

Bower's lawyers made several appeals against his conviction, which did not include a murder weapon, any witnesses to the crime or incriminating fingerprints.

The former chemical salesman and father of two was convicted of murdering contractor Bob Tate, former police officer Ronald Mayes, sheriff's deputy Philip Good and interior designer Jerry Brown. The murder allegedly occurred during a deal for a $4000 (£2609) ultra-light airplane that went south.

Prosecutors accused Bower of killing Tate, stealing the aircraft and then killing the other three victims. According to Reuters, investigators said they found parts of Tate's plane at Bower's residence and that he had called Tate. Bower also acquired a gun and exotic ammunition such as the one used during the murders, police said.

One of the victim's wives, Marlene Bushard, told reporters: "Deep in my heart, I know justice has been served. He is the right person that was convicted. It's just good to close this section of our lives and move on."

She added: "I didn't need an apology. I just needed it to be done. It's been a long time."