Johnson's family members said the schizophrenia emerged when Johnson was 17 years old.
At his arraignment, Johnson appeared agitated, blurting out statements about mind control and government experiments. He demanded a different public defender.
Last week, Johnson snapped on board a Omnibus transit bus in Rialto. Surveillance video captured what investigators describe as an unprovoked attack. Johnson allegedly stabbed Kester with a knife until the bus crashed into the curb.
Kester had been a treasured employee and the father of eight children - 6 of them were between the ages of 9 years old and 11 months.
Johnson allegedly ran from the bus and into bank, confessing to patrons what he did before laying down and surrendering.
Family members said such violence is not like him. They said he typically will feel an episode coming on and will check himself in for treatment. He gets pills, and days later, is released.
Relatives said they visited him in jail over the weekend, but Johnson didn't remember the attack. Johnson did, however, speak of a "beef" he had with a bus driver two years ago.
The district attorney said that Johnson's mental stability will be assessed in the next 45 days to determine whether he is competent to stand trial.
Investigators report that Johnson has no history of any crime on his record. His family said he tried to commit suicide twice.