Work with the 'good' Russians to rescue your informant, Nikolai.
Intel #3: Run through the swamp at mission's start. After sniping the first group of bad guys, head inside the wooden shack on the left. Next to the television set is the third intel.
Intel #4: Directly across from the room holding Nikolai is a bathroom. Next to the toilet is the fourth laptop. You should be using Night Vision at this point.