"I'm shocked," Geragos, who was in Italy, told The Associated Press in a phone call. "One of my lawyers was with him for 12 hours yesterday and he seemed in good spirits. He was looking forward to fighting this."
District attorney spokeswoman Sandi Gibbons confirmed that Miura was found dead in his cell. She said police notified her office of the death but that she did not know the circumstances surrounding it.
A phone message left with a police spokeswoman was not immediately returned.
Miura arrived in Los Angeles on Friday after a trip from the U.S. commonwealth of Saipan, where he had been held since his February arrest on a 1988 Los Angeles County warrant alleging murder and conspiracy.
He was scheduled to be arraigned Tuesday on a charge of conspiracy to commit murder.
Miura was accused of plotting to have his wife killed during a visit the couple made to Los Angeles in 1981. A bullet hit Miura in the leg, and his wife, Kazumi Miura, 28, was shot in the head. She died of her wounds a year later in Japan.
Los Angeles County prosecutors contended Miura wanted his wife dead so he could collect about $750,000 on her life insurance policies. They argued that he signaled someone to shoot the couple, although no one else has been charged.
The case remains a huge story in Japan, where the media has for decades reported its every twist and turn.
After the 1988 arrest warrant was issued, prosecutors in Los Angeles decided to work with Japanese authorities instead of trying to have him extradited. He was convicted of murder in Japan in 1994, but the verdict ultimately was overturned and Japan's highest court issued an acquittal.
