When defendant Robert Eleck wanted to impeach the credibility of a key prosecution witness, he turned to a source that has increasingly provided a treasure trove of evidence in court cases: Facebook. The messages on the witness’s Facebook page appeared to contradict her testimony that she had no contact with Eleck after he was accused of stabbing another teen at a party.

But there was just one catch. Though the woman did not deny the postings came from her Facebook account, she testified that she had not written them. Instead, she claimed, the page had been hacked into. She planted enough seeds of doubt that the trial judge ruled the messages inadmissible as evidence.