AUGUSTA, Maine — Maine State Police investigators this week worked on leads in the 2011 disappearance of Waterville toddler Ayla Reynolds, while her family announced plans to declare her deceased in order to pursue civil lawsuits against adults in the home on the night she went missing.

“We have two detectives assigned to this who have worked on the case regularly — as recently as this week,” Maine Department of Public Safety spokesman Stephen McCausland said Wednesday. “We’ve got about 40 new leads this year.”

Ayla was 20 months old when she was reported missing to the Waterville Police Department by her father, Justin DiPietro, on Dec. 17, 2011. At the time of her disappearance, Ayla was staying with her father and his then-girlfriend, Courtney Roberts of Portland, in his mother’s house. Also in the house were Roberts’ son and DiPietro’s sister, Alisha DiPietro, and her daughter.

“The three adults who were in the home at the time are withholding information,” the Maine State Police missing person post for Ayla Reynolds states. “Police believe that Ayla is probably dead.”

Investigators have ruled out the possibility that Ayla left the house on her own or was abducted and say her disappearance was a result of foul play. Yet no arrests have been made.

“We have to officially and legally receive a declaration of Ayla’s passing to take the first step to hold those accountable for baby Ayla’s demise,” a post on the Aylareynolds.com website states.

Ayla’s stepgrandfather, Jeff Hanson, said in a Wednesday email that the family is currently interviewing probate lawyers about filing the paperwork.

“Babies don’t just ’disappear,’” the post states. “Investigators had discovered Ayla’s blood in the DiPietros’ basement and have repeatedly said that the three adults who were in the home at the time are withholding information. Five years later, we are taking appropriate steps to preserve the rights of Ayla’s estate to assert future civil claims.”

The declaration will have no impact on the investigation, McCausland said.

Her mother, Trista Reynolds, was one of the many family members of unsolved homicide victims who petitioned for the creation of the state’s first cold case squad. McCausland said the case will remain active as long as resources are needed to follow up on current leads.

Maine State Police, working in conjunction with the Waterville Police Department, the Maine Warden Service and other agencies, launched the largest missing person search in the state’s history, to no avail.

“It remains the largest criminal investigation in Maine State Police history,” McCausland said, adding there are no cost estimates for the five-year-old missing person case.

After half a decade, detectives continue to dig up evidence and chase down leads, determined to close the case.

“We’ve been very open in this case from day one,” McCausland said. “There are many things we have not disclosed and [the key to solving the case] is one of them.”

The family announcement ends with a plea for those who know more about the case to come forward.

“Maine State Police and the attorney general’s office have conducted a thorough and comprehensive investigation, but still need a witness for Ayla to complete their case,” it states. “If anyone knows anything about Ayla and her short stay with the DiPietros, no matter how small, please contact Maine State Police: 207-624-7076.”