Oklahoma has executed by lethal injection Benjamin Cole, who was sentenced to death for the 2002 murder of his 9-month-old daughter Brianna Victoria Cole, over the objections of defense attorneys who argued the 57-year-old suffered from schizophrenia and was severely mentally ill.

The case highlighted a longstanding issue in the debate over capital punishment: how it should apply to those who suffer from mental illness. Meanwhile, relatives of the slain infant on Thursday decried the two-decade span between Brianna’s death and Cole’s execution.

The execution – the second of 25 Oklahoma has scheduled through 2024 – began Thursday at 10:06 a.m. CT, Oklahoma Department of Corrections Chief of Operations Justin Farris told reporters. Cole was pronounced unconscious at 10:11 a.m. CT and pronounced dead at 10:22 a.m. CT.

Cole declined a ceremonial last meal and chose not to have a spiritual adviser with him, Farris said.