Bianca Horton is shown in this file photo.

A 26-year-old mother who in May was found dead along the side of a Chattanooga road was shot six times, according to a preliminary report from the Hamilton County Medical Examiner's Office.

Bianca Horton was shot in the head, chest, arm, leg and twice in the neck, according to the report. Horton had previously survived a quadruple shooting during a home invasion in January 2015. Her daughter, then 1, was shot in the back and paralyzed from chest down. Another woman, 20-year-old Talitha Bowman, was killed, and an 18-year-old man was wounded.

Horton was a witness in that case, and some have speculated she was killed for cooperating with police and prosecutors. Police said Monday that possibility is one of several "working theories," and they cannot say for sure what motivated the attack.

Police haven't made an arrest in Horton's slaying, but Sgt. Michael Wenger said investigators have several persons of interest and are following "strong leads."

"We're working closely with the FBI," Wenger said. "It's become a pretty in-depth and complicated investigation."

Wenger would not say whether Horton was killed where her body was found in the 2100 block of Elder Street on May 25 or if she was killed somewhere else and her body left there. He also declined to say whether she was shot at close or long range.

The fact that Horton was shot multiple times doesn't necessarily indicate she knew her attacker or the attack was personal, but it does point at the shooter's intentions, Wenger said.

"It's not significant to me in any way, other than the fact that they clearly meant to kill her," he said.

Police have both circumstantial and physical evidence in the case, including video evidence and witnesses, Wenger said. Authorities don't believe anyone other than the shooter was present, but they still want to talk to anyone who witnessed events leading up to Horton's death.

Wenger also appealed to the people who were involved in her death.

"If it does turn out she was killed for the reason a lot of people, and the media especially, believe she was killed, then this is one of those cases where all of the suspects involved will be facing extremely lengthy sentences," Wenger said. "The suspects know what happened. They may have minor parts in it or major parts in it. What we really need is for someone in that circle to come to talk to us, before we get to them."

Cortez Sims, the 19-year-old charged in the 2015 quadruple shooting, remains in the Hamilton County Jail and is scheduled to appear in court on July 21, records show. A validated gang member, Sims was 17 at the time of that incident.

Contact staff writer Shelly Bradbury at 423-757-6525 or with tips or story ideas. Follow @ShellyBradbury.