STARKE, Fla. (AP) — A Florida man convicted in one of a series of suspected killings that became known as the “Hog Trail Murders” in the 1990s was put to death Thursday, becoming the state’s 15th person executed this year.

Daniel Owen Conahan Jr., 72, was pronounced dead at 6:12 p.m. after receiving a three-drug lethal injection at Florida State Prison near Starke. He had been sentenced to die for the 1996 kidnapping and strangling of Richard Allen Montgomery, whose mutilated body was found in a wooded southwest Florida area where authorities found the remains of at least six people over a three-year span.

Conahan was already strapped to a gurney with an IV in his arm when the curtain to the death chamber went up at 6 p.m. A spiritual adviser was at his feet and prayed throughout the process.

The team warden asked Conahan if he had any final statement, and Conahan replied, “No sir.” The deadly drug cocktail began to flow at 6:01 p.m. Conahan began to pant and then twitch briefly before going still. Several minutes later, the warden shook Conahan and shouted his name but there was no response.

Conahan, who had maintained his innocence, was identified by authorities as a person of interest in the other deaths, but he was never charged. He argued the evidence against him was circumstantial.

Conahan died in the nation’s busiest death chamber. Florida has carried out more than half of the 25 total executions in the U.S. so far this year under Republican Gov. Ron DeSantis, who leaves office in January.