A man who walked into a Toronto public library and shot his father with a crossbow before crushing his skull with a hammer will be eligible for parole after 10 years in prison.

Zhou Fang, 26, was sentenced to life in prison with no chance of parole for a decade after pleading guilty to second-degree murder in the death of 52-year-old Si Cheng on Dec. 2, 2010.

Fang had originally been charged with first-degree murder in the fatal attack, which he carried out inside the Main Street Library in Toronto’s east end while the facility was full with afternoon patrons.

Crown prosecutors accepted a plea to the lesser offence earlier this summer.

According to Crown attorney Mike Callaghan, Fang had suffered “long-term and horrible abuse at the hand of his father.”

The court heard that this abuse, inflicted against both Fang and his mother, caused Fang to suffer from post-traumatic stress disorder at the time he committed the murder.

Fang and his mother “suffered continuous physical and psychological abuse… abuse thoroughly documented with police and the children’s aid… one of the worst child and spousal abuse cases ever,” said Justice John McMahon.

The court heard that Fang and his mother fled all the way to Australia in an attempt to escape the abuse at the hands of Cheng, but they were denied refugee status.

They returned to Canada and hid in a home in Ottawa, where both Fang and his mother wore bullet-proof vests and fire-retardant clothing because they were certain that Cheng would find them and shoot them, or burn the house down.

Speaking outside the courtroom Toronto police Const. Bill Chan said that services are available for abuse cases, but Fang and his mother did not access them.

“We have a lot of volunteer and community organizations in the community that can help before something bad happens,” he told reporters. “We just hope that nothing bad happens again.”

Taking Fang’s situation into account, the judge gave him the most lenient sentence possible: life with no chance of parole for 10 years.

With files from CTV Toronto's Austin Delaney. Follow him on Twitter at @AustinCTV