The Latest on the killing of a couple by an attacker caught biting the dead man's face. (all times local):

8:30 a.m.

The son of a Florida man who authorities say was stabbed by a 19-year-old Florida State University student wants prosecutors to seek the death penalty.

John Stevens IV tells the SunSentinel (http://bit.ly/2bOMZZz ) he doesn't need to know exactly what led the student to kill his father and step-mother outside their house north of Jupiter on Monday night. But he wants prosecutors to seek the death penalty against the attacker, who investigators say also was biting the dead man's face when deputies arrived at the scene.

Austin Harrouff hasn't been charged in the attack. Sheriff's officials say he's still in the hospital where he's conscious but heavily sedated.

Investigators say it took several deputies and a police dog to subdue Harrouff. He tested negative for street drugs. It takes longer to test for less common hallucinogenic drugs such as flakka or bath salts.

The younger Stevens says knowing the attacker's mindset is not "super important" to him. He just wants him to "pay for what he did."

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7:45 a.m.

Investigators are still trying to piece together the sequence of events that led to an attack on a Florida couple in which a 19-year-old college student is accused of killing them and biting the man's face.

But Martin County Sheriff's Lt. Michael Dougherty tells the TC Palm (http://bit.ly/2b3AAkH ) neighbor Jeff Fisher came to their aid after hearing the screams of 53-year-old Michelle Mishcon.

Fisher told deputies Mishcon and her 59-year-old husband John Stevens III were still alive when he got there Monday night. But Dougherty says they were dead by the time deputies arrived and found Austin Harrouff on top of Stevens, biting his face.

Fisher ran home after being stabbed several times. His brother-in-law told the newspaper he was released from the hospital Thursday.

Harrouff hasn't been charged. Sheriff's spokeswoman Trisha Kukuvka says he's conscious but heavily sedated.