The story gripped the country, and is still the most expensive missing person investigation in the history of the State of Maine. Ayla Reynolds went missing on December 17, 2011 from her paternal grandmother’s house at 29 Violette Ave. in Waterville, and she's never been found. Police have been unable to charge anyone in the disappearance.

Last year, a judge in Maine declared Ayla to be dead, a legal maneuver that allowed her mother to bring a wrongful death suit.

According to the Portland Press Herald and the Morning Sentinel, the girl's mother will file that lawsuit in Maine court on Monday, seven years after Ayla was last seen.

The story, quoting family attorney William Childs, says that a press conference will be held on Monday as the lawsuit is formally filed. Childs told the paper that through a legal process called discovery, they intend to establish "how Ayla was killed, where she was killed and why she was killed."