(CNN) -- A Denver woman's frantic phone call with a 911 dispatcher was fatally cut short when her husband allegedly shot her, police say.
The phone call was in its 13th minute, and police had not yet arrived when the shot was fired.
Richard Kirk, 47, was arrested on suspicion of first degree murder.
The victim called 911 on Monday night, saying that her husband was "talking about the end of the world" and asking her to shoot him, according to a police probable cause affidavit.
She told the dispatcher that there was a gun in the house, but that it was in a safe.
The couple's three children were scared, the woman told the dispatcher, and Kirk was hallucinating, she said.
She then began to scream after seeing that Kirk had grabbed the gun from the safe.
What followed was "an apparent gunshot and the victim was not heard on the call again," according to the affidavit.
The incident has raised questions about the time it took for officers to respond to the call.
When police arrived, they found the victim dead from an apparent gunshot wound to the head.
"We will report the truth, even if mistakes were made," the Denver Police Department said about the case on its Twitter page.
Kirk was arrested, and while in the backseat of the police car told an officer that he had killed his wife, the affidavit states.
Police are investigating whether Kirk had smoked marijuana or taken other drugs, as some reports allege.