A man shot dead - allegedly by a 14-year-old boy - has been named locally as 32-year-old Lee Holt.
Mr Holt, who is understood to be a father, was hit once in the chest at a house on Barnard Close in Oswaldtwistle last night.
Police arrested a boy, 14, on suspicion of murder.
It is believed Mr Holt, whose job was painting road markings for a local tarmacing firm, had been visiting the address, a modern semi-detached house down a quiet cul-de-sac.
It is understood he went there on Wednesday night to discuss bullying allegations between children at a local school.
The father of the arrested boy is understood to run his own tree surgeon business and kept guns at the property, according to neighbours.
One neighbour said she heard a woman screaming "blood, blood!" after Mr Holt was fatally injured and bleeding heavily, and another resident attempted to resuscitate Mr Holt before paramedics and police rushed to the scene, shortly after 8.25pm.
The victim was taken to Royal Blackburn Hospital where he died a short time later while the boy was taken into custody.
Shane Murray, writing on Facebook, said: "What an absolute shame, totally shocked, how in gods name does a school argument end up with someone loosing there life!! Rip my mate Lee Holt thoughts and prayers for the family at this sad time xxx"
Another Facebook post from Martyn Cavna said: "When herd there was a shooting in Accrington never in a million years would I av thaught it was an old pal of mine ... rip Lee Holt thaught are we ur family ??"
Police have yet to formally name the deceased.
Launching a murder inquiry, Detective Inspector Pete Danby 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."
Mr Holt's family were too upset to speak when approached on Thursday.
Two blue police tents covered the front of the house, and the road was blocked by police tape with officers standing guard.
Crime scene forensic officers in white boiler suits could be seen working at the property.
The next door neighbour to the house was too upset to speak and taken away by a friend, carrying bags of possessions.
Neighbours said a family of five live at the house - the parents and three children, the eldest the boy of 14 and a younger boy and girl.