He's a well regarded therapist with an interest in cognitive psience.

[Which should be perhaps a little alarming. For this Akechi, it's even more so, knowing how far he is able to go in other worlds...]

But you see, it isn't an ordinary hospital. Mitsuru Kirijo is not a woman so easily trifled with, and I don't believe he can afford to meddle in the affairs of the Kirijo Group. Not only that, but it is my understanding that her research mysteriously disappeared the very same night she collapsed.

[That bitter smile flattens.]

I suspect that Maruki stole it. Perhaps he's keeping it hidden in order to have leverage with Shido, but that's mere speculation.