A Washington woman discovered that her husband was simultaneously married to another woman through the Facebook "people you may know" feature, which suggests friends based on mutual contacts.
The BBC reported that the woman called her husband's mother, then called the police.
The man had left his first wife without divorcing her. He changed his name and remarried, which means he may be sent to jail for bigamy.
Alan O'Neill "forgot" to divorce his first wife, Reuters wrote. Facebook suggested wife number one befriend a woman she didn't know. After browsing through photos, one of which included a photo of the "friend you may know" and of her husband Alan - previously known as Alan Fulk, before a name change - standing by a wedding cake, she gave Alan a call. Unable to reach him, she called his mother, and then the authorities.
O'Neill is charged with bigamy, since he knowingly concealed the previous marriage. Reuters writes: "Part of the reason for the prohibition [of bigamy] is duplicity -- bigamy implies that the marriages are kept separate and remain a secret."
O'Neill/Fulk faces up to six months in jail if convicted.