A toddler found dead early on Monday outside her New Hampshire home in bitterly cold weather apparently left her house just before dawn but couldn't get back inside.
Newport Police said the death of the 2 ½-year-old, whom the family only identified as Sofia, is not suspicious and "appears to be a bad accident".
The girl's grandfather, Lindsay Van Schoick, said through text message that a neighbour had found the girl. He said the family is still trying to understand what happened.
"It's rough," he said. "It was a terrible accident, a terrible accident. She (his daughter) is doing horrible. She is doing terrible. She just lost one of her children."
Van Schoick, who was at the Newport home but wouldn't answer the door, said the family had just moved into the apartment and his granddaughter may not have known her way around. He also said the front door leading outside was easy to open and the family had not had time to put bolt locks on the entrance.
"I don't think she made it up the stairs. They found her at the bottom of the stairs," he said. "There are things we will never know. We'll never know what happened."
A neighbour and her boyfriend heard cries around 04:00 on Monday but didn't see anything. They went back to bed and the neighbour later found the girl at the bottom of the stairs leading to the child's apartment. The two-storey, multifamily home sits up the hill from a busy section near a gas station, insurance office and pharmacy.
"I saw a little girl next to the bottom of the stairway, and I said to myself, 'I hope that's a doll,'" Shane Rowe told WMUR-TV. "And my girlfriend came out, and she ran out, and she went over and saw that it was actually a child."
Rowe said his girlfriend knocked on the parents' door around 07:00. Then, the mother scooped the child up, wrapped her in a blanket, and called 911.
Temperatures were below zero degrees Fahrenheit (minus 18 Celsius) overnight.
The toddler's grandfather, who lost a son five years ago, said the loss of a girl he described as "very intelligent, precocious, very stubborn and adamant" has hit the family hard.
Alan Ayotte, a neighbour of the family, said he had met them briefly and they "seemed to be fine, decent people".
Ayotte said he never heard anything overnight and only learned of the accident when emergency officials arrived early on Monday.
"It's just unbelievable that something happened like that," he said. "It's too bad that someone couldn't have prevented it."