I have been working with another postdoc on a paper, here is what happened: I presented a work of mine before it was published (but it is in my thesis and on arxiv) and he decided he will use the same exact model with a slight change. I have talked it out with him and finally with my lab adviser as he was not collaborating, and we decided to send the paper as coauthors after our adviser mediated the issue (though it was bumpy), even sorted out whose name goes first etc.
The methodology belongs to me and the application area is the same (topic), although he has written all the code practically (he said he wanted to learn and build a more modular code etc) I did contribute by writing small scripts but he ended up not using them.
My advisor has asked their collaborating institute whether I could join (the irony that my methodology is stolen but I need a pass to join the project) and they did approve it (I have all exchanges and emails). I spent countless hours discussing and working on the project with him, as he is working on another project I have little clue about the execution but he had to travel often and he made a presentation to the partner institute. I also suspect that my adviser got the patent of the code on his name as I have noticed he took my name out of contacts on github recently. I had not asked to be in the copyrights of his code but he has told me that I was going to be there relating the model. My adviser only wants to please the partner institution I am afraid. I was away for a week and before that my colleague and I saw each other very briefly and all sounded to be on track. He has run over time for the completion of the project so he is not working here anymore technically. Today I get no reply from him on multiple attempts and I learnt that he has removed his computer's hard drive and my adviser is off for vacation for an unknown time.
I suspect that my colleague will try to send off the paper we were supposed to write together without my name on it, I have email exchanges as proof but most relied on my adviser, whom I don't know if I should trust after the copyright issue. What do I do if he sends the paper without my name? Do I write to the editors? His partner institution? Is there a board for this?