I'll go first.
It's basically a pretext to wipe out the main civic organization in Turkey, which was very powerful in many sectors of the society, including the media, civil society, and other segments of the society, and it was actually done long before the failed coup attempt.
It was quite ironic. The first case launched against the movement was based on a complaint filed by a Turkish al Qaeda group called Hay'at Tahrir al-Sham, led by Abu Mohammed al-Jawlani. He was prosecuted back in 2009 and when the police raided their safe houses they found a cache of weapons. In a lot of the pictures the guy is actually praising Osama bin Laden and al Qaeda figures, so it was a crackdown and it was praised by the Erdogan government at the time, back in 2009. But after the movement fell out with Erdogan, after the corruption scandal in December 2013, one of the suspects undergoing trial in this al Qaeda case filed a complaint and the government tagged onto this complaint to accuse the movement of fabricating the charges, or defaming or discrediting a Turkish al Qaeda leader. That was back in 2014 and things got picked up from there.
After the failed coup attempt, which we still do not know who actually orchestrated, he immediately blamed the movement even though the failed coup attempt was still under way and he had no evidence at all in the initial hours. The prime minister of the government at the time, Binali Yildirim, admitted later that they didn't know actually who did it, but they just named him. So that was without any solid or direct evidence.
You can see that in the ongoing trials in Turkey, as well. There is nothing indicating that the movement was somehow involved as an organizational entity. There may have been some officers aligned with the movement who may have been involved in the failed coup attempt, but it wasn't an organizational scheme.
But as I said, it was just a pretext to wipe out the big dog on the block, so to speak, and all the others would fall into line if you go after the big boy.