Marla Cooper told ABC News that she has provided the FBI with a guitar strap and a Christmas photo of a man pictured with the same strap who she says is her uncle, Lynn Doyle Cooper.

After clarifying her childhood memories surrounding the incident and more recent conversations with her parents, she is now sure that her uncle is in fact the notorious man who hijacked and threatened to blow up a commercial plane flying to Seattle in 1971, then parachuted to the ground with $200,000 in hand.

“I’m certain he was my uncle, Lynn Doyle Cooper. Who we called L.D. Cooper,” she told ABC News.