Relevancy of statements: signed responses to summons may prove facts when witnesses are unavailable or court admits them. A signed statement made in response to a summons under section 70 is relevant to prove its contents in prosecutions if the maker is dead, cannot be found, is incapable of giving evidence, is kept away by an adverse party, or presence cannot be secured without unreasonable delay or expense; alternatively, the statement may be admitted when the maker is examined as a witness and the court deems admission to be in the interest of justice.