article: Police said the 27-year-old victim heard a knock at the door of his home in Brucehill Road, Dumbarton at 00:15. When he answered it, he was "violently attacked" by three men who he did not know. Officers said that images of the men have been captured on CCTV cameras in the area and they appealed for help in tracing them. One of the men walked with a limp and they were all in their 30s. Det Sgt Fiona Macarthur said: "This man was violently attacked on his own doorstep and it is absolutely crucial that we trace the people responsible as soon as possible. "I would like to speak to anyone who was in the area in the early hours of this morning and saw three men or anything suspicious."
summary: A man is being treated for stab wounds after he was attacked by three men on his own doorstep.