Anthony McKinney got a life sentence for running down the street.

The suburban Chicago street down which he ran, on Sept. 15, 1978, took him near the spot where security guard Donald Lundahl had earlier been shot to death. Police, still on the scene investigating, arrested McKinney, 18, who said he was running from gang bangers. With no physical evidence linking him to the crime, they ended up letting him go.

But they did not forget him. Eventually, police turned up two men who said they had witnessed the crime, one of whom said that from 50 yards away, he saw McKinney, who had no history of violent crime, point a shotgun and say, "Your money or your life." Detectives re-arrested McKinney. After a long session in the interrogation room, he signed a confession.

At trial he recanted, saying he had been coerced. At the time of the killing, he said, he was home watching the Ali-Spinks fight. His father corroborated this, not that it helped. McKinney was convicted and sentenced to life.

We are indebted to the Medill Innocence Project, which gives journalism students at Northwestern University real world experience in investigative reporting, for the preceding account. And also for the following findings, based on a three-year investigation begun in 2003:

-- McKinney was indeed running from gang bangers that night. Students found two of them who admitted chasing him, angry that he had damaged their car.

-- The "eyewitnesses" say police beat them into falsely fingering McKinney. Both had originally told police they were home watching the Ali-Spinks fight until the ninth round, which would have made it impossible for them to witness the murder.

-- The crime scene is a busy street. It is not possible to hear anything said or shouted there from 50 yards away.

-- The now-retired police officer who led the investigation had a jacket full of brutality complaints and once faced federal charges for allegedly beating a suspect.

-- A convicted killer, Anthony Drake, told students he was "present" at the murder -- and that McKinney was not.

Students finished their investigation in 2006. McKinney, now 49, still languishes behind bars, his conviction under judicial review.

Meanwhile, not content with having two crimes (i.e., the apparently still-unsolved murder of Donald Lundahl and the railroading of Anthony McKinney) on her hands, the prosecutor is busy committing a third. She's trying to kill the messenger.

Though students have already turned over copies of videotaped interviews with witnesses, affidavits and other evidence from their investigation, Cook County State's Attorney Anita Alvarez wants more. Her office has subpoenaed personal information about the students and the class: copies of their expense reports, e-mails, class syllabi, grades and grading criteria.

Through a spokeswoman, Alvarez has portrayed this as a simple attempt to gather all pertinent information. But it isn't. They already have that.

What it is, is a fishing trip. What it is, is overreach. What it is, is a crude attempt at intimidation by officers of a justice system whose shoddy work stands exposed. What it is, is a warning to the next person who dares dig up unwelcome news.

And what it is, is a fresh reminder, in this era where some of us think we can get by with bloggers and "citizen reporters," of why good journalism matters, still.

Sally Daly, Alvarez's spokeswoman, told the New York Times, "At the end of the day, all we're seeking is the same thing these students are: justice and truth."

As far as is known, she said this with a straight face.

The Innocence Project is fighting the subpoena. Here's to their success.

• Leonard Pitts Jr. is a columnist for the Miami Herald. He can be reached at lpitts@miamiherald.com.