A doctor on trial on allegations he attempted to murder his wife on a trail in Hawaii last year took the stand in his own defense Thursday.

Maui anesthesiologist Dr. Gerhardt Konig is charged with second-degree attempted murder, accused of trying to push his wife, Arielle Konig, off a cliff during a hike in Honolulu on March 24, 2025, her birthday. Prosecutors allege he then assaulted her with a rock.

Gerhardt Konig hoped Thursday to persuade a Hawaiian jury that hitting his wife repeatedly with a rock was self-defense.

“She kind of grabs my wrists, and throws herself on the ground, and she hits me with a rock on the side of the face,” Gerhardt Konig testified.

He responded “yes” when asked by his attorney if he “reacted to defend” himself “in the heat of the moment.”

But prosecutors argued that Gerhardt Konig was angered when he saw text messages that he thought indicated his wife was having an affair.

“You were mad, right?” a prosecutor asked.

“I was not mad,” Gerhardt Konig responded on the stand.

“You were not mad when you confronted your wife about these messages?” the prosecutor followed up.

“I was upset,” Gerhardt Konig said.

Arielle Konig was critically injured in the incident but survived, and she has since filed for divorce. Last week, she testified against Gerhardt Konig, telling the jury he tried to stab her with a syringe, and when that failed, struck her with a rock.

“I just started screaming, because, in my mind, he’s trying to knock me unconscious, to get to be able to drag me over the edge,” Arielle Konig said during her testimony, which has been affirmed by witnesses in the trial.

“Yes, he was hitting her with a rock,” Amanda Morris, a nurse, testified last month when asked by prosecutors what she saw Gerhardt Konig doing on the trail.

Sarah Buchsbaum, also a nurse, said she witnessed the alleged attack and called 911. She also testified last month that Arielle Konig’s “face was covered in blood.”

“I felt horrible,” Gerhardt Konig testified Thursday when asked by his defense attorney how he felt to see his wife bleeding.

In his own testimony earlier this week, Gerhardt Konig’s 19-year-old son Emile Konig referred to his father as “the defendant.” He described what Gerhardt Konig said during a FaceTime call Emile said he received moments after the alleged attack.

“That he would not be making it back to Maui, and to take good care of the younger kids, and that Ari, my stepmom, had been cheating on him. And that he tried to kill her,” Emile Konig testified.

Asked on the stand if he planned or wanted to hurt Arielle Konig that day, Gerhardt responded “no.”

Prior to his arrest in the case, Gerhardt Konig was a doctor with the Anesthesia Medical Group in Hawaii. He had previously worked as an anesthesiologist at the University of Pittsburgh Medical Center, where he had also served as an assistant professor of anesthesiology and bioengineering.

If convicted as charged, he could face up to life in prison.