A 42-year-old man admitted Friday in court that he threw a 9-year-old boy to his death off a Kawasaki condominium high-rise in March, but is pleading not guilty by reason of insanity.
Lawyers for Kenji Imai argued at his first Yokohama District Court trial session that Imai suffers a mental disorder and should not be held criminally liable for his actions.
Imai also admitted trying to throw a 68-year-old janitor to her death from the same building in Tama Ward.
Prosecutors said in their opening statement that the defendant had initially planned to kill his family because he felt they had become indifferent to him after he had been hospitalized with a mental disorder, but later gave up the plan.
The defendant "then thought about destroying a happy-looking family . . . and came up with the idea of throwing somebody from (an upper floor of) a condo complex so that his hands would not be tainted with blood," they said in a statement.
Imai stands accused of murdering Yuki Yamakawa, a third-grader at a local elementary school who lived on the 14th floor of the condominium, by throwing him from the outdoor corridor of the floor above on March 20.
Yamakawa's death was initially investigated as an accidental fall.
Nine days later, Imai attacked the janitor and attempted to throw her from an upper floor of the same building. When police probed this attack, they discovered surveillance footage that connected Imai to Yamakawa's death.