Alexandria Winship-Wright's mother reported that she went to use the bathroom and returned to discover sliding glass doors of her house open last Wednesday. Her family had moved to the home two days before Alexandria went missing. Police were notified of the toddler's disappearance shortly after noon.
Searchers quickly began searching the flooded river, which is about 40 yards from the apartment the girl lived in. There is a river retaining wall next to the dyke system, which borders an all-terrain vehicle trail.
"She should have had to go down a flight of stairs outside the building, walked over the retaining wall and up" to get to the river, Fort Fairfield Patrol Detective Stan Nicholson told FOXNews.com on Tuesday.
It's about 80 adult steps from the bottom of the steps up to the river, he added.
"We're still searching the river," Nicholson said. We're not ruling the possibility [of finding her alive] out but we have a strong suspicion she's in a river."
Game wardens will have three boats and kayaks on the river Tuesday to continue the search. They paddled the length of the river on Monday. On Sunday, two boats and 10 searchers were looking on the riverbank for any sign of Alexandria; outside volunteer groups also have been aiding the ground search.
"We've been in touch with all the power plants along the river, both here in the States and in Canada," Nicholson said. "They're all watching their nets."
Two of the girl's boots were found in the river last week; one on Wednesday shortly after she went missing, and another about three to four hours later, Nicholson said.
The rainy weather has been hampering the air portion of the search and has made the river water extremely murky. Searchers hope conditions will improve Tuesday or soon after so that more air searched can be conducted.
"Every day we're going to continue the search," Nicholson said, although he added that resources may be scaled back sometime next week.
Nicholson said a missing child's alert has been issued, but that no one in the tight-knit community recalled seeing any strange cars or individuals in the area at the time of Alexandria's disappearance. Police also checked with all area sex offenders, and said there were no signs the girl had been with any of them.