By Milo Boyd Police have ramped up the quest for answers into the unsolved murder of a pizza chef two years ago. Italian-born Carlo Giannini, 34, was found dead in a Sheffield park on May 12, 2022, having lost his life to a stab wound, a post-mortem concluded. A murder probe was launched and four knives recovered during a search of the scene. However, none could be linked to his death or identify the handler of the weapon, detectives said. Six people have been interviewed, five on suspicion of the murder and one on suspicion of assisting an offender, in connection with the case, South Yorkshir…