Human rights groups are welcoming a Mexican Supreme Court decision to free a man who claimed soldiers tortured him into confessing to a role in a drug-related massacre.

The court ruled 28-year-old Israel Arzate Melendez's confession wasn't valid because he talked to soldiers rather than prosecutors, as the law requires.

Human Rights Watch said Thursday that the decision sends a clear message that evidence obtained through torture won't be accepted. Groups and activists have complained of human rights abuses by Mexican security forces in regions where troops have been deployed to fight drug gangs.

But relatives of the 15 victims of the 2010 massacre that Arzate was accused of participating in say it is a shame that the torture allegation did away with witness testimony.