Two similar subway assaults occurred in the New York City subway in 1999. In each, a man diagnosed with schizophrenia pushed a person into the path of an oncoming train. An assault by Julio Perez, age 43, caused the amputation of Edgar Rivera's legs. The assault by Andrew Goldstein, age 29, killed Kendra Webdale. Both men had been dismissed by psychiatric facilities with little or no medication. One of the men was homeless and the other had repeatedly sought a supervised living arrangement.
Kendra's law, introduced by Governor George E. Pataki, was created as a response to these incidents.  In 2005, the law was extended for 5 years. 
A report by the New York State Commission on Quality of Care for the Mentally Disabled, November 1999, "In the Matter of David Dix (pseudonym)" http://www.cqcapd.state.ny.us/publications/dix.htm. "Despite an awareness...that Mr. Dix required a supervised setting...he was repeatedly discharged to live in an apartment...an arrangement that never successfully kept Mr. Dix from decompensating."
New York Times article, "Frightening Echo in Tales of Two In Subway Attacks," by Nina Bernstein, June 28, 1999. "In each instance that day...people with only scraps of information about Mr. Perez listened briefly and sent him on his way, to another part of the same disjointed system that had been shuttling him between hospitals, jails, shelters and the streets of New York since 1995."
New York Times Magazine cover story, "Bedlam on the Streets," by Michael Winerip, May 23, 1999. Magazine cover blurb: "Long before Andrew Goldstein pushed a woman in front of a train, he pleaded for help. He couldn't get it. The Crisis of the Mentally Ill."