Gerhardt Konig acknowledged calling his wife derogatory names and wanting her to leave her job

Prosecutors pressed the Hawaii doctor accused of trying to kill his wife during a tense cross-examination Thursday, challenging his account of a violent confrontation on an Oahu hiking trail.

Gerhardt Konig, who testified the day before that his wife attacked him first, faced pointed questions about his actions, his state of mind and his behavior in the months leading up to the incident.

During questioning at his trial, Konig acknowledged he went into what he described as “detective mode,” saying it began even before he accessed WhatsApp messages. He admitted to tracking his wife’s activity and reviewing her communications.

He testified that WhatsApp was the most frequently used app and confirmed he also looked through her emails, saying he had her consent.

Gerhardt Konig sitting in a courtroom in Maui

Gerhardt Konig sits in a Maui courtroom facing charges in the an attempted murder trial involving his estranged wife. (KHON-FOX)

Konig acknowledged that while the messages did not contain explicit sexual content, he was upset by the extent of the relationship.

“I was upset,” he told jurors, explaining his reaction was not about a single message but the overall nature of the communication.

Prosecutors also pressed him on his language, and Konig acknowledged calling his wife derogatory names, though he said that did not happen during the initial disclosure.

Gerhardt Konig standing outdoors with his wife in Hawaii

Gerhardt Konig was charged with attempted second-degree murder after he allegedly tried to kill his wife while hiking in Hawaii. (Gerhardt Konig/Facebook)

He testified that he wanted his wife to leave her job and strongly preferred she have no further contact with the coworker she was allegedly having an affair with.

Outside the presence of the jury, attorneys clashed over the scope of questioning allowed during cross-examination.

The state argued the defense had opened the door to questions about sexual coercion, including whether Konig demanded sex or threatened to disclose private information.

The judge ruled prosecutors could question Konig about sexual demands but could not characterize them as coercion.

Hawaii doctor Gerhardt Konig appearing via video in courtroom during arraignment hearing

Hawaii doctor Gerhardt Konig appears before a judge via video April 7, 2025, in Honolulu during an arraignment hearing after being indicted on allegations of attempting to kill his wife. (Marco Garcia/AP)

The court also allowed limited questioning about what was described as “digital spying,” including allegations Konig accessed his wife’s accounts, used an iPad to monitor her communications and mirrored her phone to view emails and messages.

The cross-examination followed Konig’s dramatic testimony Wednesday, in which he claimed his wife attacked him first during a violent struggle on the trail.

He told jurors the confrontation escalated after an argument over her alleged affair.

Konig testified his wife shoved him, grabbed him and struck him with a rock. He admitted striking her twice, saying he acted on instinct to protect himself.

Arielle Konig testifying in a Maui courtroom during attempted murder trial

Arielle Konig testifies in court during the Maui attempted murder trial involving her estranged husband. (KHON-FOX)

He also became emotional on the stand, telling jurors he felt “horrified” and “hopeless” after the incident.

Konig’s testimony came after two days of emotional testimony from family members, including his own son.

On Tuesday, Emil Konig told jurors his father called him after the incident and said he had tried to kill Arielle, but she got away, a claim central to the prosecution’s case.

Jurors also heard from Arielle Konig’s family, who described a relationship that had grown strained in the months leading up to the incident.

Peter Mast, Arielle Konig’s stepfather, testified there had been a “cooling” in the relationship over the past year and said, at a party in late January, Konig appeared to be pretending everything was normal.

Judith Mast, Arielle Konig’s mother, described tension and “coldness” between the couple, though she said it appeared the relationship had been improving in the period before the incident.

Prosecutors allege Konig attacked his wife on that hike in an attempted killing.