Thunder Bay police are investigating the city's first murder of the year. They say a 54 year old man died in hospital around 1 o'clock Saturday morning after he walked into a break-in in progress at a home on the 800 block of Minnesota Street. His 45 year old female friend told police he was assaulted. The victim is identified as Robert Francis Topping. Police have arrested two men and are still looking for two others aged 18 and 20 years old.