They NEVER explained how Veronica Mars found the monkey but then again this show NEVER explains how she solves any of the cases.
She literally finds some green tea and the researcher lady even sarcastically says "oh you narrowed our suspect list to anyone who has access to green tea which is pretty much everyone" and in the very next scene Veronica already found where the monkey is, who has the monkey and where they are hiding it with NO EXPLANATION as to how she figured it out from just having some leaves of green tea.
This is why this show got canceled at the end of 3 seasons because it never made any sense and they never explained how Veronica was able to magically find everything and solve every case with no evidence or explanation at all. She just magically "solves" it because she simply does. That's all the explanation you need.
She literally finds some green tea and the researcher lady even sarcastically says "oh you narrowed our suspect list to anyone who has access to green tea which is pretty much everyone" and in the very next scene Veronica already found where the monkey is, who has the monkey and where they are hiding it with NO EXPLANATION as to how she figured it out from just having some leaves of green tea.
This is why this show got canceled at the end of 3 seasons because it never made any sense and they never explained how Veronica was able to magically find everything and solve every case with no evidence or explanation at all. She just magically "solves" it because she simply does. That's all the explanation you need.