Investigative reporter Rick Perlstein writes that Rahm Emanuel failed to reach the 50% plus one threshold against a crowded field because of the widespread perception of corruption.

Some saw him as “Mayor 1%,” taking care of the powerful. But there was more:

“Perhaps what turned some voters against Rahm at the last minute—or motivated them to go to the polls in the first place on a cold Chicago day that started out in the single digits—was an Election Day exposé that appeared in the British paper the Guardian by investigate reporter Spencer Ackerman. “The Disappeared” revealed the existence of Homan Square, a forlorn “black site” that the Chicago Police operate on the West Side.

There, Chicagoans learned—many for the first time—arrestees are locked up for days at a time without access to lawyers. One victim was 15 years old; he was released without being charged with anything. Another, a 44-year-old named John Hubbard, never left—he died in custody. One of the “NATO 3” defendants, later acquitted on most charges of alleged terror plans during a 2012 Chicago protest, was shackled to a bench there for 17 hours.

It “struck legal experts as a throwback to the worst excesses of Chicago police abuse, with a post-9/11 feel to it,” the Guardian reported. And for a candidate, Rahm Emanuel, who ran on a message he was turning the page on the old, malodorous “Chicago way,” the piece contributed to a narrative that proved devastating.

“Indeed, the mayor faced a drumbeat of outstanding journalistic exposés all throughout the campaign. The Chicago Sun-Times reported on Deborah Quazzo, an Emanuel school board appointee who runs an investment fund for companies that privatize school functions. They discovered that five companies in which she had an ownership stake have more than tripled their business with the Chicago Public Schools since she joined the board, many of them for contracts drawn up in the suspicious amount of $24,999—one dollar below the amount that required central office approval. (Chicago is the only municipality in Illinois whose school board is appointed by a mayor. But activists succeeded—in an arduous accomplishment against the obstruction attempts of Emanuel backers on the city council—to get an advisory referendum on the ballot in a majority of the city’s wards calling for an elected representative school board. Approximately 90 percent of the voters who could vote for the measure did.) “