By Michael Birnbaum and Jenna Johnson
Washington Post Staff Writers
Friday, January 29, 2010; 12:15 PM
...Tofig said school officials believe that software that tracked keystrokes was put on teacher's computers via a plug-in USB device in order to obtain their passwords to the online grading system. He said that grades from three teachers appeared to have been altered.
Grades were changed for at least 30 students, according to a source familiar with the situation who requested anonymity because the investigation is ongoing...