Means of evidence

(1) The authority makes use of the means of evidence that it considers necessary, in the exercise of its due discretion, for ascertaining the facts. It may in particular 1. obtain information of every kind, including electronically and as an electronic document; 2. hear parties, examine witnesses and experts, or obtain the written or electronic statement of parties, experts and witnesses; 3. call for documents and files; 4. take a view of the object. Documents and files may also be called for in electronic form, unless something else is determined by legal provision.
(2) The parties should cooperate in ascertaining the facts. They should in particular state facts and evidence known to them. A further-reaching duty to cooperate in ascertaining the facts, in particular a duty to appear in person or to make a statement, exists only insofar as it is specially provided for by legal provision.
(3) Witnesses and experts are under a duty to make a statement, or to render an opinion, where this is provided for by legal provision. Such a duty also exists where the statement or the rendering of an opinion is unavoidable, within the framework of section 407 of the Code of Civil Procedure, for the decision on the arising, rendering, continuation, suspension, withdrawal or lapse of a social benefit, and its amount. The provisions of the Code of Civil Procedure on the right to refuse to give evidence or to render an opinion, on the challenge of experts, and on the examination of civil servants as witnesses or experts, apply correspondingly. Where the authority has engaged witnesses, experts and third parties, they receive, on application, compensation or remuneration by correspondent application of the Judicial Remuneration and Compensation Act; the authority may agree remuneration with experts.
(4) The revenue authorities must, insofar as this is required in a procedure under this Code, provide information on the income or asset circumstances, known to them, of the applicant, the benefit recipient, the person liable to reimburse, the person liable to pay maintenance, the person entitled to maintenance, or the family members counting to the household.