YOKOHAMA, Japan — Olatunbosun Ugbogu confessed to stabbing and killing a Japanese taxi driver in Yokosuka last month but claimed “overpowering” voices ordered him to do it.

The 22-year-old U.S. sailor, a Nigerian national, also said he never intended to kill the man or skip out on paying a $195 cab fare from Tokyo. Ugbogu, who hasn’t been indicted, made the statements Friday during his first appearance in Yokohama District Court.

His attorney, Yasutoshi Murakami, argued Ugbogu suffers from mental illness and needs a psychiatric evaluation. A Japanese prosecutor said murder and robbery charges are warranted, which could bring the death penalty or life in prison.

Wearing shackles on his feet, Ugbogu looked disheveled as he read from a prepared statement about his role in the March 19 stabbing death of 61-year-old Masaaki Takahashi in an alley in Yokosuka’s Shioiri neighborhood.

Takahashi was stabbed in the neck with a kitchen knife and bled to death in the front seat of his taxi, his seat belt still fastened, according to police reports.

“The voice is an overpowering voice, unresistable that gives me direction as a command on doing anything without my consent,” Ugbogu told the court.

Calling the voices “spirit friends,” he said they sound like an echo in which 20 people pronounce the same word simultaneously. Hours before the killing, Ugbogu said, they instructed him to grab a knife and take all his money — about $100 and 30,000 yen.

“I went outside and was ready to actually stab anybody, but I couldn’t find anyone outside because it was raining,” Ugbogu said.

The “voice” led him toward the Nagahara subway station, he said. He hopped a train to Gotanda Station, then transferred to another train to Shinagawa Station.

In Shinagawa, Ugbogu said he jumped the line and got into the taxi driven by Takahashi, telling the driver to take him to Yokosuka.

“We never had no conversation on the way,” he said. “All that was on my mind was to fulfill the message that I was sent.”

When they reached Yokosuka, Ugbogu said, he told the driver to turn right on a road he wasn’t familiar with and stop. Takahashi then generated a receipt and the sailor handed him a credit card.

“The driver turned his back at me and ... the voice just came up in me and said, ‘Stab him,’ and immediately I did,” Ugbogu told the court, describing how he brought the knife out of his right jacket pocket.

Ugbogu, a seaman assigned to the USS Cowpens, was declared absent without leave March 10 and taken into U.S. custody 12 days later. He was handed over to Japanese authorities April 3.

During Friday’s hourlong session, Murakami pleaded with prosecutors not to pursue robbery charges against Ugbogu because the seaman is mentally ill and did not take any money from the taxi. He also said there was no reason for the sailor to return to Yokosuka because he had deserted the Navy.

“Why was he there? He was obeying the voices he heard,” Murakami said.

“He still hears these voices, and he doesn’t know what to do with them. ... I cannot think that what he did was through sober judgment.”

Ugbogu said his problems surfaced in high school, but they were frequently misdiagnosed. In one way or another, all his friends and family have “been a victim of my situation,” he added.

Ugbogu’s mother was contacted in New Jersey but declined to comment on her son’s case. Murakami said she is a minister but declined to identify her.

“I greatly regret my action. I want to take responsibility of my action and be punished for my misbehavior,” Ugbogu told the court. “I am really sorry and remorseful of all actions I have taken for no reason. In addition to that, I would like to apologize to the U.S. Navy for my disgrace.

“I feel so lonely and helpless. My blood is gradually drying up and my bones are very weak. ... I see the end of my life really close.”

After the hearing, Murakami said police and prosecutors had manipulated Ugbogu’s story. They claim Ugbogu admitted his intent to kill but have avoided the mental illness issue, he added.

“That’s why I requested a mental examination. It’s very important for his criminal responsibility,” Murakami said. “The voices influenced his actions. I wanted to state this problem in the hearing.

“The ball is in the prosecutor’s office. I’ve thrown the ball. It is in that court now.”

Murakami expects an indictment to come down April 24, he said. A Yokohama District Public Prosecutor’s Office spokesman said the case remains under investigation and declined to comment.

Stars and Stripes reporters Chiyomi Sumida and Travis J. Tritten contributed to this story.