Frightening Echo in Tales Of Two in Subway Attacks
Case of Julio Perez, homeless schizophernic man accused of pushing Edgar Rivera onto New York City subway tracks on April 28, parallels that of Andrew Goldstein, man accused in fatal attack against Kendra Webdale in January, which provoked mounting criticism of New York State's mental health system; on day of attack he visited psychiatrist in emergency room of Veterans Hospital, police headquarters and criminal courts building, complaining in each case about his treatment at shelter for mentally ill, and telling law enforcement officers his enemies were following him; investigators say that, in each instance, people with only scraps of information about him and his violent past listened and sent him on his way to another part of same disjointed system that had been shuttling him between hospitals, jails and streets of city since 1995 (M)