On Oct. 9, 2009, in a classroom building on the campus of George Washington University, a student in a restroom was struck in the back of the head by a hammer-wielding assailant.

The assailant fled Duques Hall, in the 2200 block of G Street NW, bought an airline ticket to London the next day, and left the United States the day after that, authorities say. But in D.C. Superior Court on Thursday, a jury found Mohammed Niazi, 45, who is from the United Kingdom, guilty of two assault charges in connection with the attack, according to t he U.S. attorney’s office.

In a statement about the investigation, prosecutors said authorities had circulated surveillance images from the building in a campus e-mail alert and had received a tip that led to a nearby coffee shop. At the shop, security video and records of a credit card transaction provided them with a name.

It was not clear Friday where Niazi had been since the attack. But this year, he tried to travel though Panama. He was arrested there April 4 and returned to this country, prosecutors said.

Authorities have not identified a motive for the attack. Sentencing is scheduled for Oct. 22.