The recovery teams with the sniffer dogs had to go, there was no point sticking round, as there was to much fighting in the area. They hope they got a piece of everyone but they know there's some who may never be found.
The plan was to send investigators after the recovery was done. They haven't said, but if they had any sense they would have picked up and kept smaller pieces that looked potentially useful.
I had a picture last week of the burn field where the engines fell. The 8 - 12 inches fine broken small rubble they were standing on has been cleared, and they're on almost bare earth now. Guess the farmer wants his field back. Maybe they're dumping the bits into big drums, for lack of anything better to do, then they can be shipped back.
That port engine is worth bringing back. It is the most likely piece to have collected shrapnel that would still be there. In thinner bits it would have gone through and fallen out. They only need 1 or 2 to analyse. It is no likely to show who pushed the button .