That led to the man, correctional officer Alan L. O'Neill being slapped with bigamy charges.
According to charging documents filed Thursday, O'Neill married a woman in 2001, moved out in 2009, changed his name and remarried without divorcing her. The first wife first noticed O'Neill had moved on to another woman when Facebook suggested the friendship connection to wife No. 2 under the "People You May Know" feature.
"Wife No. 1 went to wife No. 2's page and saw a picture of her and her husband with a wedding cake," Pierce County Prosecutor Mark Lindquist told The Associated Press.
Wife No. 1 then called the defendant's mother.
"An hour later the defendant arrived at (Wife No. 1's) apartment, and she asked him several times if they were divorced," court records show. "The defendant said, `No, we are still married."'
Neither O'Neill nor his first wife had filed for divorce, according to charging documents. The name change came in December, and later that month he married his second wife.
O'Neill allegedly told Wife No. 1 not to tell anybody about his dual marriages, that he would fix it, the documents state. But wife No. 1 alerted authorities.
"Facebook is now a place where people discover things about each other they end up reporting to law enforcement," Lindquist said.
O'Neill, 41, was previously known as Alan Fulk. He has worked as a Pierce County corrections officer for five years, sheriff's spokesman Ed Troyer said.
He was placed on administrative leave after prosecutors charged him Thursday. He could face up to a year in jail if convicted.
O'Neill is free, but due in court later this month, which is standard procedure for non-violent crimes, Lindquist said.
"About the only danger he would pose is marrying a third woman," he said.