Proft brushed past the guards and introduced himself as "the great Detective Proft" without a hint of irony, then identified the culprit within minutes.

Murders at Karlov Manor

Auspicious Arrival

Target creature gets +2/+2 until end of turn. Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

"The Azorius are too obsessed with facts to see the truth that knits them together. They'll never solve this case unless I step in."
—Alquist Proft, case notes

Target creature gets +2/+2 until end of turn. Investigate.