Tests on a man who died after being Tasered by police have proved inconclusive.
Bodybuilder Dale Burns, 27, was Tasered several times at his flat in Barrow-in-Furness, Cumbria, on Tuesday night as officers tried to arrest him on suspicion of causing criminal damage.
Mr Burns, who was also sprayed with pepper spray during the arrest bid, was taken to hospital but later pronounced dead.
Sources confirmed that a post-mortem examination was unable to establish the cause of his death and further tests will now be carried out.
The Independent Police Complaints Commission (IPCC) has launched an investigation into the incident.
Cumbria Police were first called to a flat in Hartington Street at around 6.30pm after reports of a "concern for welfare" of a man inside. Officers attended 10 minutes later and after speaking to the man decided to call an ambulance.
The IPCC said: "Police attempted to arrest the man on suspicion of causing criminal damage at the flat. During the arrest, one officer discharged a Taser at the man a number of times. Another officer deployed Pava spray (commonly known as pepper spray). The Taser deployed is understood to be a conventional police weapon."
The IPCC said Mr Burns, a father of two, was restrained and taken to Furness General Hospital at around 7.30pm, where his condition deteriorated and he was pronounced dead at 8.41pm.
The IPCC later officially confirmed that the post-mortem examination, which was carried out at the Royal Preston Hospital on Thursday afternoon, proved to be inconclusive. It is now awaiting the results of further tests before a cause of death can be established.
A CCTV sweep of the area is also under way to recover any relevant footage which may assist the investigation and the IPCC has also appealed for any witnesses to come forward.