A 14-year-old boy has been arrested on suspicion of murder after a man was fatally shot in the chest.
Police were called to Barnard Close in Accrington at about 20:25 BST on Wednesday to reports that a man aged 32 had suffered a single gunshot wound.
He was taken to Royal Blackburn Hospital where he was later pronounced dead.
Lancashire Police said the teenage boy, from Accrington, is currently in custody.
Det Insp Pete Danby said: "Firstly my thoughts are with the man's family at this incredibly sad and difficult time.
"We think this was an isolated incident and believe there is no wider threat to local residents."
The force has added extra patrols in the area and the victim's family are being supported by specially trained officers, Det Insp Danby added.
Anyone with any information is asked to contact the force or Crimestoppers.