Arizona has executed another death-row inmate for two gruesome murders he and another man committed 25 years ago.

Daniel Wayne Cook, 51, was convicted of first-degree murder and sentenced to death for killing two people back in 1987. Cook spent nearly half of his life on death row at a state prison in Florence. His execution was Arizona's fifth this year, but more could be scheduled.

The most executions Arizona has conducted in one year was 7 back in 1999.