CHICAGO -- A Northwestern University professor and journalism students who spent three years investigating the case of a man convicted in the 1978 killing of a security guard believe they have evidence that shows prosecutors put the wrong man behind bars. But in the quest to prove his innocence, they may have to defend themselves, too.

Cook County prosecutors have outraged the university and the journalism community by issuing subpoenas to professor David Protess seeking his students' grades, his syllabus and their private e-mails. Prosecutors claim that since the team was made up of students, they may have been under pressure to prove the case to get a good grade.

It's a first for Dr. Protess and his investigative reporting students, who have helped free 11 innocent men from prison, including death row, since 1996. Their work also is credited with prompting then-Gov. George Ryan to empty the state's death row in 2003, re-igniting a national debate on the death penalty.

None of the students has been individually subpoenaed.

The prosecutor's office -- led by Anita Alvarez, who last year was elected Cook County state's attorney on a reputation for toughness -- said it is just being thorough, and wants to determine if students may have skewed their findings to get a good grade.

Northwestern's lawyers have filed a motion to quash the subpoenas, and the judge may act on that tomorrow, when a hearing is set to hear arguments about whether there should be a new trial in the case. In the prosecution's response, they argue that Dr. Protess and his students are not journalists and therefore are not protected by reporters' privilege.

Washington correspondent Daniel Malloy writes the "Pittsburgh On The Potomac" blog exclusively at PG+, a members-only web site of the Pittsburgh Post-Gazette. Our introduction to PG+ gives you all the details.