OMAHA -- Omaha cold case investigators have been looking for links between this week's slayings of a Creighton University professor and his wife and the 2008 slayings of an 11-year-old boy and his family housekeeper. The professor, Dr. Roger Brumback, was a colleague of the boy's father and mother at Creighton's medical school. They are Drs. William and Claire Hunter. Their son, Thomas Hunter, and their housekeeper, 57-year-old Shirlee Sherman, were stabbed to death at the Hunters' home on March 13, 2008. Police have not said how Roger and Mary Brumback were killed. Their bodies were discovered in their west-central Omaha home on Tuesday. No arrests have been reported in either case. Police won't say whether they found any links, other than the professional relationships between Roger Brumback and the Hunters.