A Metropolitan Police officer has been giving evidence on the opening day of a British man's trial in Kenya over claims he plotted attacks.
Jermain Grant, suspected of ties to al Qaeda-linked group al Shabaab, was allegedly arrested with chemicals, batteries and switches in December 2011 in the city of Mombasa.
Prosecutors say the alleged Islamic militant planned to use them to produce explosives.
Grant had a memory stick in his possession containing documents about making explosives, said Detective Inspector Stephen Ball.
Mr Ball, who has been helping Kenyan police investigate the case, told a court that jihadist documents and other materials "clearly dedicated to the making of explosives and weaponry" were found on the stick.
The detective said documents contained information on chemicals that could be used to make explosives, and ways of making booby-traps to target government officials, police or bomb disposal teams.
He said: "These files speak for themselves and show the person's interest in the construction of an improvised explosive device, and with the chemicals files show intent to obtain the materials to make such a device."
Grant, a 30-year-old Muslim convert, has been accused of working with fellow Briton Samantha Lewthwaite.
She is the fugitive widow of British suicide bomber Germaine Lindsay, who blew himself up on a London tube train on July 7, 2005, killing 26 people.
Known as the "White Widow", the mother-of-three and daughter of a British soldier is wanted by Kenyan police, and there is speculation that she was involved in last year's Westgate mall siege in Nairobi.
In December 2011, Grant pleaded guilty to charges of being in Kenya illegally and lying about his nationality, for which he was sentenced to two jail terms of two years, to run concurrently.
However, he was acquitted of robbery charges in a separate trial in Nairobi last year. He denies the charges he is facing in his latest trial.
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