Here are the NY laws governing witness tampering:
http://public.leginfo.state.ny.us/menugetf.cgi
§ 215.10 Tampering with a witness in the fourth degree.
A person is guilty of tampering with a witness when, knowing that a
person is or is about to be called as a witness in an action or
proceeding, (a) he wrongfully induces or attempts to induce such person
to absent himself from, or otherwise to avoid or seek to avoid appearing
or testifying at, such action or proceeding, or (b) he knowingly makes
any false statement or practices any fraud or deceit with intent to
affect the testimony of such person.
Tampering with a witness in the fourth degree is a class A
misdemeanor.
§ 215.11 Tampering with a witness in the third degree.
A person is guilty of tampering with a witness in the third degree
when, knowing that a person is about to be called as a witness in a
criminal proceeding:
1. He wrongfully compels or attempts to compel such person to absent
himself from, or otherwise to avoid or seek to avoid appearing or
testifying at such proceeding by means of instilling in him a fear that
the actor will cause physical injury to such person or another person;
or
2. He wrongfully compels or attempts to compel such person to swear
falsely by means of instilling in him a fear that the actor will cause
physical injury to such person or another person.
Tampering with a witness in the third degree is a class E felony.
§ 215.12 Tampering with a witness in the second degree.
A person is guilty of tampering with a witness in the second degree
when he:
1. Intentionally causes physical injury to a person for the purpose of
obstructing, delaying, preventing or impeding the giving of testimony in
a criminal proceeding by such person or another person or for the
purpose of compelling such person or another person to swear falsely; or
2. He intentionally causes physical injury to a person on account of
such person or another person having testified in a criminal proceeding.
Tampering with a witness in the second degree is a class D felony.
§ 215.13 Tampering with a witness in the first degree.
A person is guilty of tampering with a witness in the first degree
when:
1. He intentionally causes serious physical injury to a person for the
purpose of obstructing, delaying, preventing or impeding the giving of
testimony in a criminal proceeding by such person or another person or
for the purpose of compelling such person or another person to swear
falsely; or
2. He intentionally causes serious physical injury to a person on
account of such person or another person having testified in a criminal
proceeding.
Tampering with a witness in the first degree is a class B felony.