N.Y. EPT. LAW § 4-1.6 : NY Code - Section 4-1.6: Disqualification of joint tenant in certain instances

Notwithstanding  any  other  provision of law to the contrary, a joint
  tenant convicted of murder in the second degree as  defined  in  section
  125.25  of  the  penal  law  or murder in the first degree as defined in
  section 125.27 of the penal law of another joint  tenant  shall  not  be
  entitled  to  the  distribution  of  any  monies in a joint bank account
  created  or contributed to by the  deceased  joint  tenant,  except  for
  those monies contributed by the convicted joint tenant.
    Upon  the  conviction  of  such joint tenant of first or second degree
  murder and upon application by the prosecuting attorney, the  court,  as
  part  of  its sentence, shall issue an order directing the amount of any
  joint bank account to be distributed pursuant to the provisions of  this
  section  from  the  convicted  joint  tenant  and  to the deceased joint
  tenant's estate. The court and the prosecuting attorney shall each  have
  the  power to subpoena records of a banking institution to determine the
  amount of money in such bank account and by whom deposits were made. The
  court shall also have the power to freeze such account upon  application
  by  the prosecuting attorney during the pendency of a trial for first or
  second degree murder. If, upon receipt of such court orders described in
  this section, the banking  institution  holding  monies  in  such  joint
  account  complies  with the terms of the order, such banking institution
  shall be held free from all liability for the distribution of such funds
  as were in such joint account. In the absence of actual or  constructive
  notice  of  such  order,  the banking institution holding monies in such
  account shall be held harmless for distributing the money  according  to
  its ordinary course of business.
    For  purposes of this section, the term banking institution shall have
  the same meaning as provided for in paragraph (b) of  subdivision  three
  of section nine-f of the banking law.