PORTLAND, Maine — A toddler whose disappearance more than five years ago sparked the biggest criminal investigation in state history was declared legally dead on Wednesday, allowing her mother to proceed with a civil lawsuit targeting those she believes to be responsible for her death — including her father.

Cumberland County Probate Judge Joseph Mazziotti ruled that a preponderance of the evidence supports his finding that toddler Ayla Reynolds died on or around Dec. 17, 2011.

Ayla’s father told police he believes she was abducted from the home where they were staying in Waterville, but state police investigators have discredited his story. Detectives say Ayla’s blood was found in the basement bedroom where her father slept.

No one has been charged with a crime.

Ayla’s mother, Trista Reynolds, has blamed the father, Justin DiPietro, for the toddler’s death. Earlier in the week, she said she thinks a wrongful-death lawsuit is the best way to get justice.

“I’ve never wanted money out of it. I want justice,” she told New England Cable News.

Her relatives referred questions to their attorney on Wednesday. The attorney, William Childs, didn’t immediately respond to inquiries from The Associated Press.

Ayla, who was 20 months old, was staying with DiPietro when she was reported missing on the morning of Dec. 17, 2011. DiPietro told authorities that he tucked Ayla into bed the night before and that she was gone the next morning.

Ayla was last seen wearing pajamas with polka dots and the words “Daddy’s Princess” on them. She also had a soft cast on her left arm. Searches turned up no evidence of her.

Detectives maintain adults in the home know more than they’ve told investigators.

The criminal investigation remains open and active. The father, who’s believed to be living in California, couldn’t be reached for comment on Wednesday.