Police have opened a murder investigation, after a 30-year-old man was apparently stabbed to death in a home in Makiki. Police were called to a weapons case on Metcalf Street just before 4:30 a.m. Sunday. When they arrived, witnesses were trying to restrain the suspect in a struggle. Police found the victim unresponsive and performed CPR until paramedics arrived and took him to a trauma center in critical condition, but he died there. Police arrested a 26-year-old Kauai man and an 18-year-old Palolo man at the scene on suspicion of second-degree murder. Charges are pending. People at the house told the Honolulu Star Advertiser the victim was the aggressor, and the two men who were arrested were trying to defend a pregnant woman when the victim held a knife to her.