The computer, shown to Foreign Policy reporters, was found to include the typical propaganda and instruction manuals, but the physics and chemistry student who owned the laptop also had a 19-page document on how to develop biological weapons, including the bubonic plague. It included instructions on how to test the weapons in mice.
"Use small grenades with the virus, and throw them in closed areas like metros, soccer stadiums, or entertainment centers," the document says, reportedForeign Policy. "Best to do it next to the air-conditioning. It also can be used during suicide operations."
The document also contains a fatwa written by the jailed Saudi cleric Nasir al-Fahd, justifying the use of such weapons.
The laptop appears to have been owned by a Tunisian man called Muhammed, who left exam papers and pictures of himself on the laptop. Around 2,400 Tunisians had left the country to fight in Syria, the Tunisian interior minister said in June, with many of those joining Isis.
Analysts fear that the huge gains made by Isis in recent months — which have left it controlling larg parts of Syria and Iraq — could mean that the group has men like Muhammed working in occupied areas to build such weapons, Foreign Policy reported. But it is likely to remain difficult for the group to find the materials to make them, they said.