(1) tampering with evidence can surely get an officer into trouble but it will not get him the death penalty, as it doesn't automatically make an officer a co-conspirator to a murder,
Martin is correct. Texas Penal Code, section 37.09:
Sec. 37.09. TAMPERING WITH OR FABRICATING PHYSICAL EVIDENCE. (a) A person commits an offense if, knowing that an investigation or official proceeding is pending or in progress, he:
(1) alters, destroys, or conceals any record, document, or thing with intent to impair its verity, legibility, or availability as evidence in the investigation or official proceeding; or
(2) makes, presents, or uses any record, document, or thing with knowledge of its falsity and with intent to affect the course or outcome of the investigation or official proceeding.
(b) This section shall not apply if the record, document, or thing concealed is privileged or is the work product of the parties to the investigation or official proceeding.
(c) An offense under Subsection (a) or Subsection (d)(1) is a felony of the third degree, unless the thing altered, destroyed, or concealed is a human corpse, in which case the offense is a felony of the second degree. An offense under Subsection (d)(2) is a Class A misdemeanor.(c-1) It is a defense to prosecution under Subsection (a) or (d)(1) that the record, document, or thing was visual material prohibited under Section 43.261 that was destroyed as described by Subsection (f)(3)(B) of that section.
(d) A person commits an offense if the person:
(1) knowing that an offense has been committed, alters, destroys, or conceals any record, document, or thing with intent to impair its verity, legibility, or availability as evidence in any subsequent investigation of or official proceeding related to the offense; or
(2) observes a human corpse under circumstances in which a reasonable person would believe that an offense had been committed, knows or reasonably should know that a law enforcement agency is not aware of the existence of or location of the corpse, and fails to report the existence of and location of the corpse to a law enforcement agency.
(e) In this section, "human corpse" has the meaning assigned by Section 42.08.