An unidentified woman drove the boy to Dallas police headquarters Tuesday afternoon, where he turned himself in and told investigators what happened. Homicide Lt. Craig Miller said the runaway cried during the interview.
The youth was arrested on a murder charge.
"However, it's in the juvenile court system, and it'll play out through that process to determine whether or not they continue to pursue those charges," Miller said in Thursday's online edition of The Dallas Morning News.
Miller said it wouldn't be unusual for an adult in the same situation to be arrested on a murder charge.
"An innocent citizen protecting their own property is (a) different situation than an individual who possibly could be coordinating and operating a location where drugs are being sold," the lieutenant said.
Authorities are investigating how the youth, who is a runaway from a Dallas suburb, ended up where the slaying happened.
"One of his parents is deceased, and we're still undergoing the investigation to find other family members, where they may be, and how things got to this point," the lieutenant said.
Cobbs had been released from jail in September after serving time for deadly conduct. He had pulled a gun on his girlfriend or wife and threatened to kill her after she told him not to use her cell phone to call other girls, police reports say.
Dallas police have recently faced other standout cases involving youth and drugs.
In May, a 14-year-old boy was accused of dealing heroin after police raided his home and found the drug -- as well as several handguns, a rifle and hundreds of rounds of ammunition. Police said an 8-year-old relative acted as his lookout.
In July, a 14-year-old girl was accused of trying to smuggle $50,000 worth of marijuana in three suitcases on a bus from Laredo.
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