WATERVILLE — The maternal grandfather of a toddler who went missing two months ago is challenging her father to explain what happened on the night she was last seen in his home.

Ron Reynolds said Thursday his family is being torn apart because the father, Justin DiPietro, and others in the Waterville home won’t explain what happened before Ayla Reynolds was reported missing on Dec. 17.

“That eats me up every day,” an emotional Reynolds said from Portland, where he lives. “Why didn’t they protect her? Why didn’t he protect her? He was responsible for her safety and welfare.”

Ayla’s mother, Trista Reynolds, doesn’t live with DiPietro. Ayla ended up with her father in October after child welfare workers intervened while her mother, who also lives in Portland, 75 miles southwest of Waterville, checked herself into a 10-day rehabilitation program.

DiPietro told police he last saw Ayla on the night of Dec. 16 when he put her to bed. At the time, Ayla, then 20 months old, was wearing green pajamas with polka dots and the words “Daddy’s Princess” on them and had a soft cast on her broken left arm.

Police say DiPietro, his girlfriend and his sister were in the home that night but aren’t telling everything they know. DiPietro’s mother, who owns the house, wasn’t there that night, police said.

DiPietro couldn’t be reached for comment Thursday, and his mother didn’t return a message.

But a few days before Christmas, DiPietro, addressing the public for the first time, said in a statement he had “no idea what happened to Ayla or who is responsible.” He said his family and friends would do “everything we can to assist in this investigation and get Ayla back home.” He declared in another statement days later: “I would never do anything to hurt my child.”

Ayla’s disappearance garnered national attention as scores of law enforcement officers and volunteers searched for her in the week before Christmas. Law enforcement officials went so far as to drain nearby streams, and dive teams have searched the icy Kennebec River, about a mile from DiPietro’s home.

Police eventually declared that Ayla’s disappearance was a crime, and late last month they confirmed that Ayla’s blood was found in the home’s basement, which DiPietro used as his bedroom.

On Thursday, state police spokesman Steve McCausland said investigators continue to work around the clock on the case. He said the number of tips from the public has exceeded 900.

“We continue with as much energy and determination as when we began two months ago,” McCausland said. “At this point we would have liked to have had more answers, but that has not stopped the resolve to get those answers.”

Ron Reynolds, a hospital security officer and former Marine, said he was thankful to police for their efforts. And he said he’s trying hard to keep the faith that his granddaughter will be found alive.

“I just hope she’s OK,” he said.

Attorney Steve Bourget, hired by DiPietro’s family members to speak for them, says there were no drugs or alcohol in the house the night Ayla disappeared. He says the family members continue to cooperate with police.

But McCausland suggested Thursday that the DiPietros could be doing more to help investigators. He said detectives are encouraging the DiPietro family to keep Ayla’s name in the public, something the Reynolds family has been doing through a website, billboards and interviews with the news media.

“We continue to encourage the immediate family to keep Ayla in the headlines and to talk about her,” McCausland said. “One side is doing that, and the other side is not.”