Dallas police announced the arrest late Saturday night but have not yet released the man’s name.
Police received a call that there was a child dead in the street at about 6:50 a.m. Saturday.
Assistant Chief Albert Martinez has said it appeared the child had suffered a violent death and that “an edged weapon” was used.
He said it’s believed the child was killed at about 5 a.m.
The child’s name hasn’t been released.
Antwainese Square, 39, told The Dallas Morning News she alerted authorities after seeing the boy’s body while she was jogging.
She said the boy’s face was covered in blood and upper half of his body were covered in blood and that he didn’t have shoes or a shirt.
“I mean just knowing that someone out there is capable of killing a child, that alone is just unsettling, “she said.
By midafternoon on Saturday, FBI agents were focusing on a wooded trail not far from where the body was found and police were on horseback in the area.
The trail was sealed off with crime-scene tape.