Reports that West Yorkshire Police were warned about two of the suicide bombers who attacked London on 7 July last year have been denied by the force.
Martin Gilbertson, 45, told the Guardian newspaper he alerted police to the activities of Mohammad Sidique Khan and Shehzad Tanweer in October 2003.
But the West Yorkshire force said they had "no knowledge of any contact with Mr Gilbertson" prior to 7 July 2005.
Tanweer and Khan were among four men whose bombs killed 52 people in London.
The Guardian reported that Mr Gilbertson had produced anti-Western propaganda videos and encrypted e-mails for Muslims at an Islamic bookshop in Beeston, Leeds.
He told the paper he went to his local police station to report his concerns, but was told to write to West Yorkshire's police headquarters.
He said he sent material including the names of Khan and Tanweer to the force's Wakefield HQ, but heard nothing back from police.
Officers from the force, who interviewed Mr Gilbertson following the 7 July attacks, said they never received anything from him.
In a statement, West Yorkshire Police said: "He states he addressed this to West Yorkshire Anti-Terrorist Squad.
"Although no department of that name exists, we have checked all departments where material of that nature would be most likely sent and they have no record of it being received."
The force added that after 7 July Mr Gilbertson passed some CDs to a national newspaper journalist, who then handed them to the police.
"The material has been examined and contains Islamic extremist propaganda including video clips and web material," the police statement said.
It added that the material was "understood to be freely available in the UK, easily accessible and can be readily downloaded from the internet".
"None of the video clips contains material which would suggest the four bombers or other individuals were planning any form of attack."