Cunningham was last seen leaving her home on Thursday to catch a school bus in Polk County. A man was in custody and will be charged with murder, authorities said.

The body of missing 11-year-old Audrii Cunningham was found in the Trinity River in Texas, officials announced Tuesday.

Don Steven McDougal, 42, in custody on an unrelated manner, will be charged with capital murder in connection with her death, Polk County District Attorney Shelly Sitton said at a news conference.

A case will be filed “based on all the evidence,” she said.

Sheriff Byron Lyons said information from the suspect, cellphone data and social media imagery sent in by citizens led them to the body off Highway 59 in the county.

A local water authority lowered the water level of the river to assist divers in their search, the sheriff said. Her body was with a medical examiner, who would determine an exact cause and manner of death, he said.

Cunningham had not been seen since she left her Polk County home on Thursday at about 7 a.m. to catch a school bus, officials said.

But she never got on that bus or made it to school that day, according to Polk County Sheriff’s deputies.

An Amber Alert was issued for the 4-foot-1 child with blonde hair and blue eyes. She was wearing black pants, a black hoodie with white lettering and black tennis shoes on Thursday.

McDougal was called “one of the persons of interest” involved in the case when he was arrested Friday on suspicion of aggravated assault, in an unrelated incident, officials said,

McDougal lives in a trailer behind Audrii’s home and is considered a family friend who’d occasionally take the girl to the bus stop or to school, officials said.

A small children’s backpack was found at the Lake Livingston Dam, not far from the Cunningham family home, authorities said. Trinity River feeds into the lake.

A $10,000 reward had been posted for any information leading to the arrest and prosecution of the person responsible for Audrii’s disappearance.