On Tuesday, a jury in central New York convicted the husband of Irish-born woman Caroline Coffey of murder.
Blazej Kot, 25, said during the trial that he suffered from a mental disorder, saying an "impostor" had replaced his wife and it was his duty to kill her.
Kot slashed his wife's throat as she went for a job on a park trail in Ithaca, N.Y., last year.
Kot, a Cornell University doctoral student from New Zealand, murdered his wife, set fire to their home to destroy any evidence and then tried to take his own life.
The jury took two days to deliver its verdict: guilty of murder, arson and tampering with evidence.
Coffey, who was born in Ireland and moved to Philadelphia with her parents when she was a toddler, was a post-doctoral researcher at Cornell.
The pair met and fell in love there two years ago. After a brief romance, they tied the knot.
They were only married eight months when Kot murdered her.
Kot will be sentenced on May 25. He faces 25 years to life in prison.