Thinn, step-brother to Associate Education Minister Nikki Kaye, appeared at San Diego Superior Court today (New Zealand time), Fairfax reported.
The court heard that Thinn needed two more months of evaluation before any assessment could be made on whether he was mentally fit to stand trial.
Fairfax reported that Thinn appeared in court with his hands and ankles shackled.
He will be back in court on May 10.
The Aucklander was arrested in San Diego last June after a man entered a Chula Vista bank brandishing a hammer and a flare gun.
The man reportedly fired two shots with the flare gun and used the hammer to try to smash a bullet-proof partition.
News reports at the time said no one was injured.
A friend of Thinn's told the Herald they had met at Auckland's Selwyn College, after Thinn left Auckland Grammar School.
He considered himself a close friend and would be trying to contact Thinn in prison to offer support.
The old schoolmate, who asked not to be named, said Thinn had gone through some personal issues over the years and had been failed by those around him.
"He should have never left the country."
Thinn's mother died a number of years ago and he inherited a large amount of money, the friend said.
He bought an inner-city apartment on Lorne St. He also owned a Mercedes.
The two-bedroom apartment was featured in Herald Homes in June 2011.
In an interview, the then-accounting student said he wanted to make his home a unique and hip place to live.
"I decided to make some alterations and put a fish tank in the wall to make the apartment feel alive as opposed to a sterile hotel environment.
"When I am studying, I like to hear water in the background. It's calming.''
Thinn, a lover of hip-hop and rap, often posted videos of himself rapping to lyrics he had written under the rap artist name: BigMac and Richochet Rocket.
