A laptop that once belonged to the Islamic State of Iraq and Syria (ISIS) contains documents that explain how to make bubonic plague bombs, The Daily Caller reported on Friday.

The laptop was grabbed by a moderate Syrian rebel group during a raid against ISIS. It contained 35,347 files in 2,367 folders filled with training instructions and ideological justifications for their plight, according to Foreign Policy.

The owner of the laptop, Tunisian national Muhammed S., was learning how to build biological weaponry. He studied chemistry and physics at a Tunisian university. The computer contained a 19-page document with the details, explaining that "the advantage of biological weapons is that they do not cost a lot of money, while the human casualties can be huge" and the way to do it is to "use small grenades with the virus, and throw them in closed areas like metros, soccer stadiums, or entertainment centers" near air conditioners.

Another document, 26 pages long, was also found on the computer and contains a fatwa by Saudi cleric Nasir al-Fahd, who is currently imprisoned in Saudi Arabia.

"If Muslims cannot defeat the kafir[unbelievers] in a different way, it is permissible to use weapons of mass destruction," the fatwa says, according to Foreign Policy. "Even if it kills all of them and wipes them and their descendants off the face of the Earth."

The laptop also contained videos of Osama Bin Laden, manuals on making bombs, tips for stealing cars and lessons on how to use disguises to avoid getting arrested while traveling from one location to another, Foreign Policy revealed. Nothing on the ISIS laptop suggested that the group had these dangerous weapons in their possession.

Symptoms of the bubonic plague include swollen lymph nodes in the groin, armpit or neck, along with fever, fatigue and muscle aches, according to the Mayo Clinic. The plague can result in death if treatment isn't received within 24 hours.