A judge in Mexico has freed four men accused of lobbing grenades into a crowd celebrating Mexico's independence day in 2008, killing eight people.

The Federal Judiciary Council said the judge declared the men innocent, ruling that three of them had been tortured into signing confessions.

From the time they were arrested almost seven years ago, the men maintained their innocence. They said they weren't even in Morelia, the capital of the western Michoacan state where the crime occurred.

Later, 16 people came forward to back up the men's story that they were in the Pacific coast port of Lazaro Cardenas.

The judge ruled the defendants' rights were violated by the release of a video of them confessing without a lawyer and the falsification of a signature on the confession.