Prosecutors in the murder case against the man charged with killing University of Iowa student Mollie Tibbetts are accusing the defense of attempting to hide a subpoena meant as a “fishing expedition” of Tibbetts’ banking records. Prosecutors weren’t aware of the subpoena until after it had it had been served on Bankers Trust in Des Moines and returned to court records Jan. 21, according to a motion filed Tuesday by Assistant Iowa Attorney General Scott Brown. Defense attorneys for Cristhian Bahena Rivera, charged with first-degree murder, directed the subpoena, which was issued Jan. 15 by the Poweshiek County Clerk, Brown said.