Revelation

HELEN

 Devon Matins is working with The Last Order, Rowena Pearson is the one assigned to protect him. He was killed by The Covenant, she is presumably also with them. Her husband was made to confess to the governor's murder.

 Wait. Do not tell me…

 ...

 ...

 ...

 Oh great makers, could it be? Is this case somehow related to the big showdown between those two giants?

 It is possible. 

By the looks of it, Governor Matins has been working with The Last Order for years now. He protects them, they take out his targets; it is a give and take relationship. But now he has been killed by The Covenant, and The Last Order's operative is missing. 

 If The Covenant does indeed have her, then…

The Last Order leaves none of their own behind, not a single member. They are known for their loyalty to each other. If The Covenant has an Order operative, then it could have very well sparked the war.