#mtgmkm

He knew about Teysa's death way too early. Like Kaya had just left the agency, and the ghosts wouldn't have told anyone.

He was at the party, talking to two of the (intended) victims (Teysa and Aurelia)

Etrata was wearing Selesnya threads. There's no way he wouldn't have noticed

The hammer assassin had white fur on his coat, likely from one of the Ledev Guardian wolves (if not Voja himself)

This seemed to be the most important piece of evidence, if Proft's reaction is anything to go by

Also, after this evidence was discovered, someone released the mole god in the evidence room. This was the only real piece of physical evidence that could be there.

Eating a seed and turning into moss is a very Selesnya spin on the classic cyanide capsule

Assassins are being brainwashed using psychoactive pollen, again in the Selesnya wheelhouse.

Kaust is one of the Ravnican Agency of Magicological Investigations' fast-rising stars. He has an exceptional talent for investigative work and a charismatic personality that convinces even the most reluctant witnesses to trust him. In addition to the Agency's comprehensive resources, he cultivates his own personal network of friends and informants. This network allows him to keep a finger on the pulse of the local community and hear news—often before anyone else.

For those who don't know him well, his gentle demeanor deceives them into thinking he's just a grunt concerned with solving cases and little more. In truth, his mildness hides a deep resentment against the guilds, which he believes are restricting the Agency's ability to solve cases by clinging tightly to their own jurisdictional rights. To Kaust, criminal convictions aren't nearly as important as the health of a community. His solution: take matters into his own hands. If turning in a culprit is for the greater good, then he hands the case over to the appropriate authorities, just as he should. But if giving up a culprit would do more harm than good, he's not above simply "misplacing" a case file or using his personal network to leak information that gives the culprit a chance to disappear.