This role is the Triad version of the Jailor. It has the ability to jail and role-block one player each night that follows a day with no lynch. The Interrogator can speak anonymously with the jailed person at night, and optionally execute them.
If a Mayor reveals, it is probably in the Triad's best interest to kidnap and execute him. Careful as this may strongly indicate that there's a Interrogator in play.
Kidnapping an Amnesiac can let you talk with them anonymously and maybe convince them to take on a Triad role.
Jailing either an Investigator or Sheriff can give the same effect as role-blocking them. By jailing them, you make them useless, slowing down the Town.
Jailing the following roles wastes a night, as well as gives them unnecessary night immunity:
Mayor: Mayor can not normally do anything during the night, and you would only be giving him night immunity
Survivor: Persuading them to side with the Triad at a later point will give you the advantage of winning if there is supposedly a tie between the Town and the Triad. They might even be thankful for the night immunity, but it wastes a night for the Triad.
Citizen: As Citizens do nothing during the night, this will give them free night immunity and waste your night.
Mason: The only benefit of kidnapping a Mason would be to prevent them from talking with their teammates, but this will generally be useless.
Jailing a fellow Triad member (if the save permits) without charges or without a reason to use a charge may be wise if there is no need for the Interrogator to jail someone that night. This ensures that they will survive the night (short of an invulnerability-piercing Arsonist attacking them) and continue to be an asset to the team.
Do not always execute instantly when an important role reveals to you, this may indicate there's a Interrogator in play and other captives might not reveal useful information. Try to gather clues from your captives.
Listen to your teammates - they can help you decide whether to execute or not. Try not to answer them back at the night chat, as your captive might find it out of context and understand that you are actually a Interrogator.
Stays in Triad's night chat, even when in Interrogator chat.
The rest of the Triad can see what the Interrogator and the kidnapped person is saying.
The Interrogator can reactivate the ability to "feign" a kill. The target will still believe they are about to be executed, but nothing will happen as night concludes if the charge has already been used.
The Interrogator's execution CAN be used in conjunction with the standard Triad kill similar to Informant.
If the Triad have both an Informant and an Interrogator, along with the Dragon Head's kill, a total of 3 kills can be be preformed in one night.