\u00a0The mystery surrounding the missing Dutch tycoon Tob Cohen yesterday deepened after his estranged wife Sarah Wairimu Cohen was arraigned on murder charges. The decision to prefer murder charges against her came even as the fate of the Dutchman remained unknown. Wairimu, however, did not plead to the charge as High Court Judge Charles Kariuki directed that she undergo a mental assessment to ascertain if she is fit to stand trial. He ordered her remanded at the Lang\u2019ata Women\u2019s Prison pending the mental health test. According to a charge sheet filed in court by the Director of Public Prosecutions (DPP), Wairimu is alleged to have killed Tob Chichou Cohen on the night of July 19 and 20 within Nairobi county jointly with others not before the court. The defence led by lawyer Phillip Murgor opposed the plea taking, saying there\u2019s no complete charge because prosecution has yet to produce any evidence before the court.