(ABC News)-- The family of a death row inmate who was executed with a new drug concoction is planning to sue the state of Ohio for "cruel and unusual punishment," arguing that he was used as an "experiment."
The family of Dennis McGuire, 53, watched him die for 26 minutes, during which he was heard having gasping, snorting and making other sounds of distress. McGuire's execution in Dayton, Ohio, was the longest since the state reinstituted the death penalty in 1999, according to The Associated Press.
"There's one claim that will certainly be made and that will be alleging that the Eighth Amendment was violated," the family's attorney Jon Paul Rion told ABC News. "The punishment in this case was cruel and unusual."
In a press conference Friday, McGuire's children, Amber and Dennis McGuire, tearfully recounted watching their father die.
"It appeared to me that he was fighting for his life but suffocated," McGuire's son told ABC News affiliate WKEF-TV in Dayton, Ohio.
"I can't think of any other way to describe it than torture," McGuire's attorney told WKEF-TV. "We don't think Mr. McGuire should have been an experiment for the State of Ohio."
Rion told ABC News the suit was less about financial damages and more trying to stop a similar event from happening.
"This event may create an opportunity for the courts and the state to stop and look at what we're doing and see if it's economically and morally right," Rion said. "We're seeking to change in the system."
Rion said the family plans to seek a temporary injunction to halt any future executions in the state as well.
Ohio Executions Face Obstacles After Unusual Death
McGuire was executed for the 1989 rape and murder of Joy Stewart, who was eight months pregnant at the time.
Last week McGuire's lawyers protested the use of new drugs in his execution since he risked "air hunger," in which he would experience terror as he tried to grasp for breath.
McGuire was executed with a mixture of the sedative midazolam and the painkiller hydromorphone, which has been approved since 2009 but never used until last week.
Other more common drugs were not used after their European manufacturers refused to allow them to be used for executions.
The Associated Press contributed to this article.