The remains of missing toddler Evelyn Mae Boswell are believed to have been found in Tennessee on a relative's property over two months after the child first went missing, authorities said.

The Tennessee Bureau of Investigation and Sullivan County Sheriff's Office told the public at a press conference on Friday they found the remains of what is thought to be the 15-month-old from Blountville, Tennessee, ending a nearly three week search for the child.

Authorities weren't alerted to Evelyn's disappearance until 18 February when the child's grandfather told the Department of Children's Services that family members hadn't seen her for two months.

An Amber Alert for the child was issued on 19 February, starting a 17-day search that spanned across three different states.

"This is certainly not the update we had hoped to provide this evening," TBI spokeswoman Leslie Earhart said on Friday.

The remains will be sent for an autopsy and official identification, the TBI confirmed.

Investigators said they were still in the early stages of the investigation to discover what happened to the child.

Her remains were found on a property belonging to a relative of the child's mother, 18-year-old Megan Boswell, in Blountville. Tommy Boswell Sr., Evelyn’s grandfather, lives at the home and first reported the child as missing in February, WJHL-TV reports.

The mother was then arrested just over one week after the Amber Alert was issued for making a false report.

Police have accused her of lying to investigators about her daughter's whereabouts by initially saying the child was with her father, Ethan Perry, according to court documents. But Mr Perry is stationed in Louisiana with the US Army and did not have the child.

The woman then later said Evelyn's grandmother, Angela Boswell, took the child to a campground in Mendota, Virginia. Investigators searched multiple campgrounds in the area and could not find any signs of the young girl.

An exact timeline for when Evelyn went missing remains uncertain after both the mother and grandmother gave conflicting reports to police. The child is believed to have been last seen around 26 December.

Her mother remains in police custody on a $25,000 bail after a judge refused to lower the amount despite her lawyer saying she has no previous criminal record.