Innocent until proven guilty; it's one of the pillars on which most justice systems are built. But occasionally, a crime takes place that enrages the public to such a degree that a suspect's guilt is judged before legal charges have been filed.
George Zimmerman's shooting of Trayvon Martin, a 17-year-old African-American, in Florida last month is one such case. The resulting debate about race and justice in America has been fierce; Mr Zimmerman may still be charged with murder. Vigilantism, however, does no one any good - particularly not an elderly couple who have been caught up in the storm through no fault of their own.
On Friday, filmmaker Spike Lee tweeted to his 240,000 followers what he believed to be Mr Zimmerman's home address in Sanford, Florida. Except it wasn't the correct address.
In fact, it was that of a married Florida couple, who are both in their 70s and have resided in their lakefront property for over 10 years. The atmosphere surrounding the case has become so poisonous that the couple now fear for their lives.
Mr Lee's tweet may have endangered innocent people; it was bad enough when he was simply trying to endanger Mr Zimmerman.