A homeless man charged with stabbing a Columbus State Community College professor and a homeless woman charged with causing a bomb scare at Port Columbus have each been found mentally incompetent to stand trial.Both have been hospitalized in an effort to bring them to trial within one year. Their cases are unrelated. 36 year old Isaac Rotich was arrested in June after a part-time mathematics professor was stabbed on the CSCC campus. Police say Rotich knew the man, who has recovered from his injury. Port Columbus police arrested 57 year old Klara Bias in August after she allegedly left a threatening letter and a fake explosive at the facility.