Scotland Yard has passed on material found in Abu Qatada's home to Danish authorities to reportedly investigate a connection with a controversial Islamic publisher.
The Metropolitan Police are investigating suspected extremist material found during a search of Qatada's taxpayer-funded home in London in March.
After receiving information from the Met, Copenhagen police are exploring whether Qatada used publisher Al Nur Islamic Information to print hard copies of the material.
The publisher was founded by Said Mansour, a Moroccan-born Dane, who was jailed for three and a half years in 2007 for promoting terrorism.
Mansour, who was released from prison in 2009, was convicted of distributing around 12,000 CDs, DVDs and videos inciting jihad against the West, including footage of Wall Street reporter Daniel Pearl being beheaded.
Danish national newspaper Berlingske claims to have seen a 70-page document allegedly written by Qatada and printed by Al Nur Islamic Information.
A Met spokesman confirmed material found at Qatada's home was passed to the Danish authorities, but could not say what further action had been taken.
Qatada has offered to return to Jordan - provided an anti-torture treaty is ratified.
The hate-preaching cleric's barrister made the surprise offer as he attempted to get released from prison at an immigration tribunal.