The search for Audrii Cunningham came to a heartbreaking end on Feb. 20, five days after the 11-year-old from Livingston, Texas, left home to catch the bus to school and never made it onboard.

Amid an exhaustive investigation involving local, state and federal authorities, divers recovered the child's body from the Trinity River under the U.S. Highway 59 bridge, according to Polk County Sheriff Byron Lyons. Authorities previously announced that a small backpack that likely belonged to a child had been found Feb. 16 near the Livingston Dam, about 10 miles upstream.

"My heart aches with this news and I express with my deepest sympathies and condolences to everyone who knew, who cared for and loved Audrii," Lyons said at a news conference following the grim discovery. "The sheriff's office, we will continue to process the evidence that has been gathered to ensure justice for Audrii."

At the time they had a person of interest who was already in custody on an unrelated felony charge, Polk County District Attorney Shelly Sitton told reporters, and her office was in the process of preparing the "appropriate arrest warrant."

And on Feb. 21, Don Steven McDougal was charged with capital murder in connection with Cunningham's death. 

He had been staying in a camper behind the house where the fifth-grader lived with her father and grandmother, according to authorities.

Audrii Danielle Cunningham's family reported her missing at around 5:30 p.m. on Feb. 15 after she didn't come home from school that afternoon, according to the Texas Department of Public Safety, Southeast Region. Investigators soon learned that the girl never made it to Creekside Elementary, where she was in the fifth grade, nor was she on the bus to school.

An Amber Alert was issued that night for the child, last seen wearing black pants, a black hoodie with white lettering and black high-top tennis shoes. She was carrying a red Hello Kitty backpack.

Don Steven McDougal, described by authorities as a friend of the Cunningham family, was arrested in connection with an unrelated assault case the next day—and on Feb. 17 was identified by the Puck County Sheriff's Office and TDPS as a person of interest in Cunningham's disappearance.

Sheriff Byron Lyons told reporters when it was still a missing-child case that McDougal had said he left the house with Cunningham the morning she went missing, hence their belief that McDougal was the last person to see her.

McDougal had walked Cunningham to the bus in the past and even driven her to school on occasion, the sheriff said.

As multiple law enforcement agencies and volunteers from the community combed the area, Cunningham's mother Cassie Matthews said she couldn't believe "the stuff you see on TV" was happening to her.

"There is not one feeling you feel, its a roller coaster, you are broken, you are mad, you are empty and right now I am empty," she told NBC affiliate KPRC 2. "She has so many opportunities ahead of her, and she deserves every right to be able to reach those opportunities."

The search for Cunningham ended tragically on Feb. 20 when divers found her body in the Trinity River under the U.S. 59 bridge. A large rock had been tied to the body, according to a charging document filed the next day in Polk County and obtained by KPRC.

Speaking to reporters, Lyons thanked water management authorities who had slowed the flow from the Lake Livingston reservoir, which lowered the water level of the river, in order to aid their search.

Lyons would not go into detail but said there was "enough evidence" to suspect murder.

The Harris County Medical Examiner subsequently determined Cunningham's cause of death to be "homicidal violence including blunt head trauma," their office confirmed to E! News, and the manner of death is homicide.

McDougal was charged with capital murder on Feb. 21 and remains in Polk County Jail after being denied bond, according to county inmate records. It remains unclear if he has an attorney yet, with no lawyer listed in court or jail records. 

The Associated Press reported that the justice of the peace who released the criminal complaint said McDougal indicated he did not want a court-appointed attorney.

Cell phone data, video footage and other forensic evidence showed that McDougal—who was questioned after being arrested Feb. 16 for an unrelated offense—"lied about his whereabouts and activities" on the day Cunningham disappeared after they left her house in his 2003 Chevy Suburban, according to the charging document.

Phone data, video analysis and some information provided by McDougal himself ultimately led authorities to the area under the US 59 bridge where they found Cunningham, Lyons told reporters. He noted that videos sent to authorities from members of the community through social media had proved helpful.

Phone records and videos ultimately placed McDougal at "three locations of interest," the charging document stated, and "evidence in connection with the defendant and the child victim" was recovered at two of those places.

Additionally, the document continued, the rope used to tie the rock to the girl resembled rope seen by law enforcement in McDougal's vehicle during a traffic stop two days prior.

McDougal had knocked on doors and otherwise appeared to be concerned for Cunningham's welfare, Lyons told reporters Feb. 20, but the sheriff believed the suspect was "trying to give the appearances that he has no play or he's not at fault in her disappearance."

McDougal has a criminal record dating back to at least 2001, according to court records obtained by KRIV and USA Today. He was sentenced to two years in prison in 2008—but credited for 527 days—after pleading no contest to two counts of enticing a minor with intent in Brazoria County, Texas.

Per an offense report, he pleaded to the lesser charge after initially facing a felony count of indecency with a child for the alleged March 2007 incident. (At a Feb. 19 news conference, Texas Department of Public Safety Lt. Craig Cummings said that McDougal had not been required to register as a sex offender.)

These court records also showed, per USA Today, that McDougal was sentenced in 2010 in Harris County to four years in prison for aggravated assault with a deadly weapon, and in September 2022 he completed a two-year sentence in the Texas State Penitentiary at Huntsville for unauthorized use of a vehicle in Liberty County.

His Feb. 16 arrest for aggravated assault with a deadly weapon stemmed from an August 2023 case in which he's accused of stabbing a man in the back, according to records obtained by KHOU News 11. Per the records, after Cunningham went missing the alleged victim recognized McDougal as the person who stabbed him and called the Polk County Sheriff's Office.

Meanwhile, Matthews went from hoping for her daughter's safe return to attending a prayer vigil in her honor on Feb. 21. The mourners wore purple, Cunningham's favorite color, and brought purple balloons. A shrine of notes, teddy bears and purple flowers also sprung up near the site where her body was found.

"I am beyond blessed to be able to give birth to something that...she was perfection," Matthews said during the gathering, per KPRC. Encouraging everyone to light their candles, she added, "Hopefully, with all of our candles together, it'll be bright enough, you know, maybe she could see it."