Asha Rangappa is a senior lecturer at the Jackson Institute for Global Affairs at Yale University. She is a FBI former special agent, specializing in counterintelligence investigations. Follow her @AshaRangappa_. The views expressed in this commentary are her own. View more opinion at CNN.

(CNN) President Donald Trump finally got Ukraine to announce an investigation — though not the one he was hoping for.

On Thursday, Ukraine's Interior Ministry announced a criminal probe into alleged surveillance against then-US Ambassador Marie Yovanovitch by people linked to Trump's lawyer Rudy Giuliani.

Asha Rangappa

The investigation provides a stark counterpoint to Trump's own attempt to coerce Ukraine's president to announce an investigation of his political rival, and what it reveals could deepen the controversy over Trump's actions beyond his impeachment trial.

First, the speed with which Ukraine opened this investigation shows that, given a valid basis, it would not hesitate to investigate potential criminal activity. The Interior Ministry moved just days after public disclosure of text messages between Lev Parnas, an associate of Giuliani's, and Robert Hyde, a GOP congressional candidate who claimed that he had tracked Yovanovitch.

By contrast, Ukraine President Volodymyr Zelensky resisted Trump's demands last year for an announcement of an investigation into the Bidens. Zelensky was reluctant even though he had much to gain from complying with Trump's demand, including vital military aid to counter Russian aggression and, possibly, an official welcome at the White House.