The husband of Sheila Keen Warren, who's accused of dressing up as a clown and killing his first wife nearly three decades ago, insists his second wife is "falsely accused."

In an ABC News "20/20" interview husband Michael Warren said, "This is very serious and very unfair.” 

Marlene Warren Wellington was killed 27 years ago when a person dressed as a clown walked up to her front door in Florida and fatally shot her.

There had been no arrests in the case until this fall, when police detained Sheila Keen Warren on Sept. 27 in Virginia. Authorities believe that Sheila is the “killer clown,” as the suspect in the case has come to be known.

Prosecutors have charged her with first-degree murder and say they will seek the death penalty.

Michael  has denied having any involvement in his first wife's death.

The full ABC News "20/20" story will air Oct. 20 at 10 p.m. ET.