Family testifies in Kot's US trial

An Auckland couple have taken the witness stand in an American court to try to explain why their son slashed his wife's throat.

Barbara and Leszek Kot travelled from East Auckland for the trial of Blazej Jakub Kot, 25, who is pleading a psychotic disorder to defend a second degree murder charge.

The court heard that Kot's feelings of being watched were strengthened by the New Zealand Government investigating his family's internet connection.

He is accused of fatally slashing Caroline Coffey's throat on a jogging trail in Ithaca on June 2, 2009, then setting fire to their apartment to cover up the evidence.

Coffey died a month after the pair celebrated their second wedding in Costa Rica.

Macabre facts of the case were revealed this week, including Kot's attempts to take his own life by cutting his throat - after looking up "how to kill neck artery" on the internet.

In a videotaped interview Kot told a psychiatrist his feelings of being watched strengthened during his teens when his mother received a call from the New Zealand Government investigating whether the family internet connection was being used to hack computers.

"It put into my mind or strengthened the idea that someone, somewhere was watching me," Kot said.

He told the psychiatrist he was uncomfortable and defensive around security cameras, and he always had the feeling he was being chosen for a special purpose.

"It was always with me," he said, his voice raspy from his self-inflicted neck injuries.

Details of Kot's mental illness were also exposed, the Ithaca Journal reported.

His lawyer Joseph Joch said since the age of 15, Kot had eccentric thoughts including fantasies that people were watching him with cameras through electrical outlets, or that he might be picked to be a secret agent.

Barbara Kot told the court her son was "always a very quiet and sensitive child" as well as attentive, creative and interested in technology.

He spent a lot of time on his computer and reading technical manuals, she added.

Kot had a tense relationship with his father, an engineer, and she mediated disagreements the pair had, Barbara said.

"Blazej was always a non-confrontational person," she testified. "He took everything seriously, but he didn't argue much."

Leszek Kot established authority over the family, and his relationship with Blazej "was not excessively warm and close," said Kot's sister Lucja Kot.

Leszek Kot testified that he "was the person who had the last word".

As a father, he admitted he was demanding because he wanted Kot to succeed.

Kot, who was studying at Cornell University when he married Coffey, had a research paper rejected and was upset, but appeared to calm down after encouragement and advice from his family.

The jury will begin deliberating later this week. If convicted he faces 25 years to life in prison.