A man who killed four people including his brother in 1997 will be put to death in Indiana – the state’s first execution in 15 years.

Joseph Corcoran, 49, was on death row since his 1999 conviction and, despite late appeals on the grounds that he was severely mentally ill, is set to be executed Wednesday by lethal injection at Indiana State Prison. 

Corcoran fatally shot his brother James Corcoran, 30, his sister's fiancé Robert Scott Turner, 32, and two other 30-year-old men, Timothy G. Bricker and Douglas A. Stillwell, inside his family home in Fort Wayne on July 26, 1997.

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Five years earlier, he was acquitted in the shooting death of his parents after the jury found insufficient evidence to convict him.

Indiana’s last state execution was in 2009 when Matthew Wrinkles was put to death for killing his wife, her brother and sister-in-law in 1994. Thirteen executions have been carried out in Indiana since Wrinkle's execution, but those were initiated and performed by federal officials in 2020 and 2021 at a federal prison.

Since Wrinkles was put to death, the state suspended state executions because a combination of drugs used in lethal injections had become unavailable. There has been a years-long nationwide shortage because pharmaceutical companies — particularly in Europe, where opposition to capital punishment is strongest — have refused to sell their products for that purpose.

Indiana Gov. Eric Holcomb, a Republican, announced in June that Corcoran’s execution was to go ahead after the state acquired a drug — pentobarbital — which can be used to carry out executions and is used by multiple states in lethal injections.

Corcoran was being held at the Indiana State Prison in Michigan City.

Corcoran's attorneys had fought his death sentence for years, arguing that Corcoran was severely mentally ill, which affected his ability to understand and make decisions. Corcoran exhausted his federal appeals in 2016. Earlier this month, his attorneys asked the Indiana Supreme Court to stop his execution but the request was denied.

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His attorneys felt that the denial gave some bit of hope to stave off the execution as the justices were split 3-2.

"Given that it is a close case, it shouldn’t be rushed through," defense attorney Larry Komp said previously. "He’s so extremely mentally ill. We think he’s irrational. We’ve never had a fair process."

Corcoran wrote the justices a handwritten affidavit this month saying he was done litigating his case, although his attorneys said it was a sign of his mental illness, per the Associated Press. 

"I am guilty of the crime I was convicted of, and accept the findings of all the appellate courts," Corcoran wrote.

Corcoran fatally shot the four victims as he was under stress because the forthcoming marriage of his sister to Turner would necessitate moving out of the Fort Wayne home he shared with his brother and sister, according to court records.

He awoke to hear his brother and others downstairs talking about him, loaded his rifle and then shot all four men, records say. 

After the shootings, Corcoran asked a neighbor across the street to call the police. When they arrived, Corcoran told them, "You might as well just arrest me," per the Tampa Bay Times. 

While jailed, Corcoran reportedly bragged about fatally shooting his parents.

One of Corcoran’s sisters, Kelly Ernst, said she believes the death penalty should be abolished and that her brother’s execution won’t solve or change anything. 

She criticized the execution for taking place so close to Christmas.

"I’m at a loss for words. I’m just really upset that they’re doing it close to Christmas," she said. "My sister and I, our birthdays are in December. I mean, it just feels like it’s going to ruin Christmas for the rest of our lives. That’s just what it feels like."

Earlier this year, Alabama became the first state to use nitrogen gas for an execution when it carried out the death penalty for convicted killer Kenneth Smith. 

The execution method, which has been criticized for being inhumane and a form of torture, killed Smith after he appeared to shake and writhe on the gurney, sometimes pulling against the restraints before several minutes of heavy breathing until breathing was no longer perceptible.

Fox News’ Landon Mion and the Associated Press contributed to this report.