A Guam court hearing the criminal case against a local man who killed three Japanese tourists in a knife and vehicle rampage last year on Wednesday pushed back the start of his trial to June, an official said.

Joshua Tenorio of the Judiciary of Guam said in an email that at a pretrial hearing earlier in the day for the Feb. 12, 2013, incident, Judge Anita Sukola changed the date of the jury selection and start of Chad De Soto's trial from April 7 to June 9 "in the interest of judicial efficiency."

The pretrial conference date of March 19 remains unchanged.

Tenorio disclosed that the prosecution has submitted a witness list comprised of 138 individuals, of whom 12 are from Japan "and would have to be flown to Guam to participate in the trial."

Tenorio told Kyodo News earlier this month that the "significant delay" in the trial of the case is due to the psychiatric and forensic evaluations that had to be conducted on De Soto, following his "not guilty by insanity" plea.

Desoto, 22, is accused of plowing his car into Japanese tourists and stabbing others and a local woman with a knife on the night of Feb. 12 last year in Guam's main tourist area of Tumon. Three Japanese died, and 10 others and the local woman were wounded.

He was charged with multiple counts of aggravated murder and multiple counts of attempted aggravated murder, and is being detained at the Guam Department of Corrections.

The most serious charge of aggravated murder carries a penalty of life imprisonment without the possibility of parole.