Unavailability Defined

(a)Unavailable as a witness includes situations in which the deponent:

(1)persists in refusing to testify concerning the subject matter of his deposition despite an order of the judge to do so;

(2)testifies to a lack of memory of the subject matter of his deposition;

(3)is unable to be present or to testify at the hearing because of death or then existing physical or mental illness or infirmity; or

(4)is absent from the hearing and the proponent of his deposition has been unable to procure his attendance by process or other reasonable means.

(b)A deponent is not unavailable as a witness if his exemption, refusal, claim or lack of memory, inability or absence is due to the procurement or wrongdoing of the proponent of his deposition for the purpose of preventing the witness from attending or testifying.