A Middlesex County jury is considering whether to convict a Wayland man of first-degree murder in the death of his former girlfriend.
Prosecutors say 20-year-old Nathaniel Fujita strangled and stabbed Lauren Astley in July 2011, then dumped her body in marsh. Both were 18 at the time and had graduated from high school just weeks before.
His lawyer claims Fujita experienced a psychotic episode at the time of the killing, and must be found not guilty by reason of insanity. Defense attorney William Sullivan says Fujita had sustained repeated head injuries while playing football and suffered from depression.
In closing arguments on Tuesday, prosecutor Lisa McGovern rejected that claim, saying Fujita acted with "deliberate premeditation."
"There is no psychosis fairy who magically sprinkles a dose of psychosis on the defendant," she said.
At one point, McGovern wrapped the bungee cord used to strangle Astley around her own neck and asked the jury to think about the young woman's injuries.
Fujita is charged with first-degree murder, two counts of assault and battery with a dangerous weapon, and one count of assault and battery. If convicted, he faces life in prison without the possibility of parole.
If jurors find him not guilty because of lack of criminal responsibility, Fujita would be committed to a mental health facility.
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