There is more than one question that accrues to this subject.
1) was the person who opened the drapes the same person who murdered the assassins?

2) was the brief interim between the attempted murder and the locating of the assassin's bodies sufficient time for them to have been murdered at that location or murdered some place else and their bodies carried or drug to where they were found?

3) Why were the bodies located next to what appears to be a drainage pipe (in Texas we call that a tinhorn)? Was that their intended escape route (as someone posted above, why was the compound end of the pipe not grated or otherwise rendered impassable by a human)?

4) Of course, how did the assassins gain entry to the compound?

5) What was used to murder the assassins? A knife? A pistol with a silencer?