Jailor is currently able to click on the jail button next to the original informant spot and the button next to the informant's target (current informant) is not there. Possibly he can do it through typing jail also but not tested. It let's Jailor easily determine who currently informant is.
Informant (3) killed n1, Jailor (Jeremiah) d2 was able to click the button next to where 3 used to be and it told him he is going to jail 2 who is currently Informant. There was no button to jail at all next to 2.