(a) The court may require that any testimony admitted as evidence in a proceeding to declare heirship be reduced to writing and subscribed and sworn to by the witnesses, respectively.
(b) Except as provided by Subsection (c), in a proceeding to declare heirship, testimony regarding a decedent's heirs and family history must be taken:
(1) from two disinterested and credible witnesses in open court;
(2) by deposition in accordance with Section 51.203;
(3) by a recorded statement of facts contained in:
(A) an affidavit or instrument that satisfies the requirements of Section 203.001; or
(B) a judgment of a court of record as specified by Section 203.001(a)(1)(B); or
(4) in accordance with the Texas Rules of Civil Procedure.
(c) If it is shown to the court's satisfaction in a proceeding to declare heirship that, after a diligent search was made, only one disinterested and credible witness can be found who can make the required proof in the proceeding, the testimony of that witness must be taken:
(1) in open court;
(2) by deposition in accordance with Section 51.203;
(3) by a recorded statement of facts contained in:
(A) an affidavit or instrument that satisfies the requirements of Section 203.001; or
(B) a judgment of a court of record as specified by Section 203.001(a)(1)(B); or
(4) in accordance with the Texas Rules of Civil Procedure.
(d) Notwithstanding any other law, a person interested in an estate solely because the person is a creditor or has a claim against the estate may serve as a witness under this section if the person is otherwise a credible witness.