No action will be taken against the firm that provided police with the Taser weapons used in the stand-off with gunman Raoul Moat, the investigating force said.
Northamptonshire Police said firearms offences were committed but it was not in the public interest to take any action against Pro-Tect Systems, whose operations director Peter Boatman is thought to have killed himself shortly after the company's licence was revoked.
The firm breached the terms of its licence by supplying X12 Tasers, which were still being tested by Government scientists, directly to police involved in the Moat manhunt, the Home Office said.
Mr Boatman was "destroyed" by the furore caused by criticism of his firm for supplying the Tasers used during the stand-off, his business partner Kevin Coles said. His body was found at his home in Reynard Way, Kingsthorpe, Northampton, on October 1, just three days after the Home Office revoked Pro-Tect Systems' licence to import and sell Tasers.
Mr Coles, Pro-Tect's managing director, said there was "no doubt" his colleague's apparent suicide was linked to the week's events.
"He was a proud man and he felt ashamed at recent developments," Mr Coles said. "He spent all his life involved in officer safety and what happened was a result of him being worried about the welfare of officers. He knew there was something there that would offer the officers protection and that was what his motive was. The furore over it destroyed him."
Pro-Tect breached its licence by supplying the X12 Tasers and XRep ammunition, which were still being tested by the Home Office, directly to two police forces.
Home Secretary Theresa May revoked the firm's licence to import and sell Tasers following an investigation into the use of the weapons at the end of one of Britain's biggest manhunts.
The stand-off with the steroid-addicted former nightclub doorman ended the seven-day manhunt which was triggered when Moat shot his former girlfriend, Samantha Stobbart, 22, killed her new boyfriend, Chris Brown, 29, and blinded Pc David Rathband, 42.
But the precise sequence of events regarding the discharge of the XRep Tasers in relation to Moat firing his sawn-off shotgun has not been established and is under investigation by the Independent Police Complaints Commission (IPCC), the inquest into his death was told.