Monks of the Way of Velma pedge to seek out criminals and wrong-doers. The receive specialized training to be more aware of, and in tune with, their environment.  They are also trained in criminology and forensics. They are often called upon by communities or the authorities to act as independent investigators. If you have a problem, and no-one else can help you, maybe you should call on the Monks of Velma.

Unmask Foe

Upon choosing this tradition at 3rd level, though a strenuous course of training you become more attuned to your surroundings. You gain proficiency in Perception & Investigation.If you already have proficiency in either of the listed skills you can instead choose to double your proficiency bonus for any ability check you make that uses the chosen proficiency.

Moreover, beginning at 3rd level when choosing this tradition, if you strike a foe in a disguise (including illusionary disguises such as Disguise or Alter Self), the disguise falls away for one round. You do not need to state that you are using this ability, it automatically happens.

If unmasking a magical disguise, the monk may overcome a spell level equal to one third of their current Monk level, i.e. a Third Level monk can cause a foe using a 1 level spell or Cantrip to disguise themselves, to be revealed. Likewise, a Sixth Level monk unmasks a foe using a 2 level spell to disguise themselves. Non-magical disguises are automatically unmasked.

Detect Lies

At 6th level, as a reaction, you may spend 1 ki point to determine whether a statement that was made during the past round was truthful, or not. The ability does not discern which part of the statement was truthful, just that at least part of the statement was untruthful.

Great Investigator

Whenever you make an Intelligence (Investigation) check, you can spend 1 ki point to gain advantage on the roll.

Also, starting at 11th level, your senses are so attuned to your environment that you are not disadvantaged, or effected by blindness nor darkness - you gain the Blindsight ability (with a radius of 30’). You may also spend a ki point to be aware of the location of any invisible creatures within a 60’ radius, for one round.

Fade from Sight

At 17th level, you can use your action to become invisible for up to an hour. You remain invisible until you make an attack or cast a spell. Once you use this ability, you can’t use it again until you finish a short or long rest. During this action, if you spend 3 ki points per person or creature you wish to effect, you can make those selected creatures within a 60’ radius forget that they had even seen you in the first place (DC 15 plus the monk’s Wisdom modifier).

Alternatively, you can spend 5 ki points and shift yourself and your equipment onto the ethereal plane as an action. This plane shift lasts for up to an hour and requires concentration. The monk can leave the etheral plane as a bonus action. As above, once you use this ability, you can’t use it again until you finish a short or long rest.