Emile Konig, 19, said that Gerhardt Konig told him his stepmom was cheating on him and he tried to kill her.

Hawaii doctor Gerhardt Konig appears before a judge via video during an arraignment hearing after being indicted on allegation of attempting to kill his wife in 2025.Marco Garcia / AP file

The son of a Hawaii doctor accused of bashing his wife’s head with a rock during a birthday hike testified in his father’s attempted murder trial Tuesday, saying his dad told him he planned on taking his own life after he tried to kill Arielle Konig.

Emile Konig, 19, said that Gerhardt Konig made the disclosure during a FaceTime call on March 24, 2025, the day authorities say he attacked his wife on the Pali Puka Trail, northeast of Honolulu.

During the call, Emile Konig told jurors, Gerhardt Konig said that his wife was cheating on him and that he tried to kill her.

Emile Konig recalled his father telling him that “he would not be making it back to Maui and to take good care of the younger kids.” Emile Konig added that his father said he planned to jump from a cliff and the son said he told his father not to.

The son testified for less than an hour. He did not look at his father as he entered the Oahu courtroom.

Prosecutors have alleged that Gerhardt Konig pushed his wife toward a cliff while the couple was on a hike for Arielle Konig’s birthday. Deputy prosecuting attorney Joel Garner said that Gerhardt Konig, an anesthesiologist, came at her with a syringe and hit her in the head with a rock.

Konig, 47, has pleaded not guilty to second-degree attempted murder. His attorney has said that his client acted in self-defense, striking his wife with a rock after she began fighting with him.

During the FaceTime call, Emile Konig said his father never mentioned having to defend himself.

In testimony last week, Arielle Konig said the alleged assault happened after her husband asked her to pose for a cliff-side selfie. She said she felt uneasy about the location and asked him to move so she could get by safely.

He grabbed her and pushed her toward the cliff, she testified, and she threw herself to the ground to try and grab hold of trees and shrubs. The anesthesiologist climbed on top of her, she said, and had a syringe in his hand.

“Nobody’s coming to save you,” Arielle Konig recalled him saying.

After she batted away the syringe, Gerhardt Konig picked up a rock and began striking her in the head, she testified. She screamed, Arielle Konig told jurors, and escaped after she heard another hiker say she was calling 911.

Body camera video played during the trial showed the hikers helping Arielle Konig, who had a bloody face and a bandage wrapped around her head.

In the months before the attack, Arielle Konig testified, her husband discovered an “emotional affair” she’d been having with a co-worker. They’d gone to counseling, she said, and appeared to be repairing the damage she’d caused to their relationship.