The following article contains spoilers from I Am Batman #10, on sale now.
The origins of the villainous Manray are still unclear, but his motivation certainly isn't. The New York City serial killer has been targeting people of influence who he believes are corrupt, specifically those who are on a secretive dossier known as the Hotlist, and I Am Batman #10 (by John Ridley, Christian Duce, Rex Lokus, and Troy Peteri) has just shed light on some of the mystery behind the list.
A call from Batman's friend, Hadiyah, explained that the Hotlist is a collection of powerful individuals and their darkest secrets. Theoretically, anyone who possesses the list has a way of making the listees do anything they want out of fear of having their secrets exposed. However, the Hotlist is also a myth, and Manray has not been revealed to possess it in any form. This raises the question of whether he is actually using the list or just making up his moves as he goes along.
Manray's first two targets were undoubtedly corrupt, but his latest, Mayor Villanueva, is of uncertain morality. Still, there is no evidence to rule out hidden corruption. Regardless, as it currently stands, the possible corruption of the mayor does not begin to match the depravity of the previous victims, at least not at first glance.
This disconnect is what brings Manray's crusade into doubt. The killer has shown no evidence of how he decided to target the victims as of yet. The depths of their corruption ran so deep, however, that is seems impossible for Manray to have acted without additional information.
This, along with Manray's unstable personality make it highly unlikely that he could have schemed and planned to acquire such a list, at least not without angering some very powerful people. This raises the possibility that Manray doesn't really have the list, but is being fed its contents by an unknown source. That is, of course, assuming the targets are even on the list.
The very nature of the list, if it actually exists, makes it a prize that many would kill to obtain. The power that comes with having the ability to blackmail wealthy and politically individuals would be heavily guarded, so Manray acquiring such a list seems doubtful. Even moreso, the villain isn't blackmailing anyone, but rather downright eliminating powerful people he sees as corrupt.
This alone may provide some answers. Manray is clearly not using the Hotlist for its intended purpose. He has turned it from a treasure trove of information into a hit list. Assuming that he is being assigned his targets, whoever actually possesses the Hotlist is in effect manipulating the disturbed killer for their own mysterious purposes.
All of this suggests that there is a hidden mastermind in the shadows who is using Manray as a puppet. Ironically, this creates a dark parallel to Batman who also wants to put an end to the corruption that is running rampant throughout the city, but is willing to do so within the confines of the law.