NEW YORK (AP) — A former New York stockbroker-turned-Islamic State group militant was convicted Tuesday of becoming a sniper and trainer for the extremist group during its brutal reign in Syria and Iraq.

The trial of Ruslan Maratovich Asainov, a Kazakh-born U.S. citizen, was the latest in a series of cases against people accused of leaving their homelands around the world to join the militants in combat.

“Today’s verdict in an American courtroom is a victory for our system of justice" and against the Islamic State group, Brooklyn-based U.S. Attorney Breon Peace said in a statement. Asainov's lawyers had no immediate comment.

A onetime broker who doted on his toddler daughter, Asainov converted to Islam around 2009 and later quit his job and started watching radical sermons online, his ex-wife testified. He abruptly left his family in Brooklyn in December 2013 and made his way to Syria as IS stormed to power.

In a case built largely on Asainov’s own words in messaging apps, emails, recorded phone calls and an FBI interview, prosecutors said he fought in numerous battles and built a notable profile in IS by becoming a sniper and later an instructor of nearly 100 other long-range shooters.

“The evidence has shown that people died as a result of the defendant's conduct. It is time to hold him accountable,” prosecutor Douglas Pravda told a Brooklyn federal court jury in a closing argument.

Asainov, 46, didn't testify, telling the court he was “not part of this process.”

His lawyers didn't dispute that he went to Syria and affiliated with the Islamic State group, but they argued that his accounts of his role were boasts that had no firsthand corroboration and didn't prove anyone died because of his conduct.

“Nobody's arguing to you that Mr. Asainov's view of the world is not a very warped view," defense attorney Sabrina Shroff said in her summation, asking the jury “not to confuse his views with what is needed to convict him beyond a reasonable doubt.”