A 14-year-old old boy has been arrested on suspicion of murder after a man was shot at a house in Accrington, Lancashire, on the night of 24 October.
Police were called following reports that a 32-year-old man had been shot in the chest at a house in Barnard Close in Oswaldtwistle.
The man was taken to Royal Blackburn Hospital but later died from his injuries.
A murder investigation was launched and a 14-year-old old boy was arrested in connection with the shooting. The teenager remains in police custody for questioning.
Police say they are treating the shooting as an isolated incident and there is no threat to the wider community.
DI Pete Danby from Blackburn Police said: "Firstly my thoughts are with the man's family at this incredibly sad and difficult time. They are being supported by specially trained officers.
"We are in the very early stages of our investigation and have a number of officers on with enquiries.
"We think this was an isolated incident and believe there is no wider threat to local residents, however, we have stepped up patrols in the area to offer some reassurance to the community.
"If you have any information that you think could assist us with our investigation, please contact us immediately."
Anyone with information can call 101 quoting incident reference LC-20171025-1407.
Alternatively independent charity Crimestoppers can be reached anonymously on 0800 555111 or online at crimestoppers-uk.org.