Fengxian District People's Court has sentenced a 38-year-old Jiangsu Province man to compulsory treatment at a psychiatric hospital instead of prison time for stabbing his sister and her mother-in-law to death in March, the court said Monday.

The defendant, Zang Bijun, was the first in Shanghai to be sentenced under an amended law that allows mentally ill individuals deemed unfit for trial to be sent to compulsory psychiatric treatment, according to a court press release.

The amendments to the Criminal Procedure Law of the People's Republic of China took effect at the beginning of this year.

Zang stood accused of murdering his two relatives with a kitchen knife and then attacking several pedestrians on Jinqian Road near his sister's home in Fengxian district on March 27.

Zang's family said he had been experiencing symptoms of schizophrenia since 2009, especially paranoia, according to the press release. The paranoia was extreme enough at times that he occasionally carried a knife to protect himself from perceived threats.

His family sent him to a hospital for two months after he began exhibiting the symptoms, the court said. He was on medication, but he stopped taking it in June or July 2012 because he believed the drugs were harmful.

The court said he did not fully understand his own actions when he attacked his relatives.

Zang had traveled to his sister's home on March 26 with the hope of finding a job. It was unclear what set off Zang the following day. His sister had not mentioned that Zang had behaved strangely while in Shanghai.

After the murders, Zang rushed outside and began attacking strangers on the street. Police officers and residents were eventually able to restrain him, the court said.

The court sent Zang to Ankang Hospital, a psychiatric institution run by the police.