Cheapest priced copy (Murders at Karlov Manor): $0.35 at Card Kingdom, near mint, their price list as of .
Forensic Researcher 
Creature — Merfolk Detective · 1/3 · Uncommon · Murders at Karlov Manor · #58
{T}: Untap another target permanent you control.
{T}, Collect evidence 3: Tap target creature you don't control. (To collect evidence 3, exile cards with total mana value 3 or greater from your graveyard.)
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Murders at Karlov Manor | 58 | Uncommon | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 2 February 2024If you can't exile enough cards to meet or exceed the required mana value, you can't choose to collect evidence at all.
- 2 February 2024Once you've announced that you're casting a spell, players can't take actions until you've finished doing so. Notably, opponents can't try to remove cards from your graveyard to stop you from collecting evidence.