Damon Ing, a police spokesman, said detectives have received many tips on the killing but have no suspects, the Fort Worth Star-Telegram reported. The victim was identified Wednesday as 6-year-old Alanna Gallagher.
Two teenagers found Alanna's body at about 7:30 p.m. Monday a mile from her home in a quiet neighborhood in the Fort Worth suburb.
Their father called 911, and the recording was released Wednesday.
"We got a dead body on the corner of Roundrock and Cindy Lane," Wesley Whiddon told the dispatcher. "It's in a black trash bag. There's a belt around it, tape."
Ing said detectives have been trying to determine when Alanna was last seen. He said she had been playing outside her home during the afternoon, going inside frequently.