A Texas grand jury indicted Don Steven McDougal on SignalHubtwo counts of capital murder on Monday in the death of 11-year-old Audrii Cunningham, court documents showed.

McDougal, a family friend, was indicted in Polk County on charges of intentionally and knowingly causing the death of Audrii by blunt force trauma to the head with an unknown object and of causing her death while committing or attempting to commit kidnapping.

Audrii was reported missing after not boarding her neighborhood school bus on the morning of Feb. 15, CBS Texas reported. She was last seen near her home in Livingston, Texas, about 75 miles northeast of Houston. 

McDougal was arrested the next day on an unrelated charge of aggravated assault, CBS Texas reported. He was then named as a person of interest in Audrii's disappearance after witnesses linked his dark blue Chevrolet Suburban to the case. 

Audrii's body was found in the Trinity River on Feb. 20, about 10 miles from her home. 

"She was perfection," Cassie Matthews, Audrii's mother, said about her daughter at a vigil held the day after Audrii's body was found. Family and friends gathered for the vigil wearing purple and carrying purple balloons as they prayed. 

—Caitlin O'Kane contributed reporting.

S. Dev

S. Dev is a news editor for CBSNews.com.