Doubtful a hit job, we don't even know if the engine was shut down by the crew for a fault or if it failed catastrophically. It could have been anything from a birdstrike, surge, compressor stall, low oil pressure, or any number of reasons. Besides it flew back and landed, taking out one engine isn't going to cause the crew that much trouble, targeting the aircraft in the cruise at altitude is the usual way they take them down, or a take over remotely from the ground.

Do we even know what aircraft type it was?