CHICAGO—Even before Cook County State’s Attorney Anita Alvarez formed her Conviction Integrity Unit one year ago to deal with potential wrongful convictions, the case of Daniel Taylor had presented prosecutors with a particularly thorny problem: how to resolve a case in which Taylor, plus seven other young men, confessed to a double murder though records show he was in a police lockup when the crime occurred.

Twenty years after his arrest, Taylor’s confession carries the day for prosecutors. Though much has been learned about why teenagers sometimes falsely confess—Taylor was 17 when arrested—prosecutors point to his long and detailed confession as the most powerful piece of evidence in the case.

For Taylor’s attorneys, who returned to court two weeks ago seeking the right to continue to appeal his case, mounting evidence that shows he was in the Chicago police lockup at the old Town Hall precinct underlines their contention he could not have committed the slayings at 8:45 p.m. on Nov. 16, 1992, as prosecutors charged.

The records show Taylor was arrested for disorderly conduct at 6:45 p.m., booked into the lockup at 7:25, had his charges approved at 9:45, and was released on bail at 10.

Others have taken note of Taylor’s case. The 7th U.S. Circuit Court of Appeals has expressed concern about the case, noting Taylor’s powerful claim of innocence and questioning his confession. The Illinois attorney general’s office has written of its concern that, for nearly two decades, prosecutors failed to turn over documents to the defense that buttress Taylor’s alibi, an allegation the prosecutors deny.

That concern did not translate into immediate action, however. Instead, it has led Taylor, now 37 and having spent more than half of his life behind bars, back to Cook County Circuit Court, where prosecutors have suggested that the records showing Taylor in jail somehow are wrong.

In many ways, Taylor’s case shows how difficult it is for a prisoner to win freedom when DNA or other scientific evidence is not at play; indeed, even cases in which DNA is involved can be tough for inmates, particularly when confessions are at issue.

“Conviction integrity means not putting innocent people away, but also making sure that there’s a fair and constitutional process. If these records weren’t turned over to the defense, then Daniel Taylor’s trial wasn’t fair and constitutional, and Daniel’s conviction has no integrity.”

Taylor and seven others were charged with murder in the shooting deaths of Sharon Haugabook and Jeffrey Lassiter in an apartment near Clarendon Park, on the city’s North Side. According to police and prosecutors, four suspects went into the apartment while the other four acted as lookouts. All eight, police said, confessed and implicated each other—meaning to undermine one of the confessions undermines them all.

Taylor was taken into custody more than two weeks after the shootings. After he was charged with the murders, Taylor remembered that he had been arrested on the night they occurred and told the detectives who had been questioning him. The police found lockup records supporting Taylor’s account, and in fact his attorney at trial presented those records as well as the testimony of some of the police officers.

Prosecutors argued that the records were inaccurate, and a jury convicted Taylor. A judge sentenced him to life in prison.

The petition Taylor filed Jan. 31 adds to the information that supports documents showing he was in the station’s lockup. Two employees—one a sworn officer, the other a civilian aide—who worked in the station said in sworn affidavits that, although they do not remember Taylor specifically, the records are clear that he was in the lockup.