Cumbrian gunman Derrick Bird was embroiled in a major tax investigation and was facing serious financial difficulties, a friend has said.
Bird's fear that he may go to prison may have been the spark that led him to go on a killing spree in Cumbria, shooting dead 12 people before taking his own life in woodland, according to the latest theory.
The taxi driver had told friends the Inland Revenue was investigating him for an undeclared £60,000 in his bank account.
Friend and fellow taxi driver Mark Cooper said Bird was scared of prison, adding: "He didn't want to go."
The claims follows reports that Bird may have argued with colleagues and family members before going on the rampage.
Police have been removing his personal effects from his house as they continue to search for a motive.
