western forces. >> reporter: july of this year, a guided missile slams into an egyptian warship in the mediterranean. january 2014, egyptian military helicopter blasted out of the sky with a surface-to-air missile. high profile strikes claimed by isis in sinai, terror group's lethal affiliate. they've launched countless ied attacks, including one which wounded four americans in september. they've killed egyptian security forces with sniper fire, and targeted their commanders. >> they have led assassination attempts against higher-up security figures, some undercover and successfully assassinated them. >> reporter: particularly skilled at operating on the inside. >> isis in sinai have a proven track record of infiltration, recruited number of insiders inside the egyptian military, inside egyptian police forces. >> reporter: ability to pull