Lopez, whose body was found the following day in a wooded area in nearby Owens Cross Roads, was identified last week through dental records, Madison County Sheriff's Office officials said in a news release.
Sheriff's Office spokesman Lt. Donny Shaw described Lopez's cause of death as "heinous" but declined to say how she was killed, WAFF reported.
"It's a very brutal means of death and whenever the public learns of it, it's going to be shocking and it's going to be upsetting a lot of people," Shaw told the news station. "We want to deliver that information so that we don't harm the upcoming cases and trials that will be had."
Credit: Madison County Sheriff's Office
Credit: Madison County Sheriff's Office
Investigators believe that the teen was killed where her body was found.
Bethel Lemley, the owner of the property where Lopez was found, said her son-in-law spotted the girl’s body in some weeds near her driveway.
"My daughter said, 'Mama, you can see her foot and see her leg,'" Lemley told WAFF. "I couldn't see it, but they did."
The homeowner said she could not understand who would commit such a crime.
"Who could have done such a cruel thing?" Lemley said. "Kill somebody and throw them off like a dog; like an animal."
The homicide case began as a death investigation when Lopez's body was found. At that time, detectives were asking the public for help identifying the person found.
The teen was described as wearing red pajama pants with gingerbread men on them, as well as a pink undershirt and black tank top. A news release indicated that she also had a cerebral shunt.
Gina Long, a substitute teacher who taught Lopez at Challenger Middle School, in Huntsville, described the girl as quiet and sweet in an interview with WAFF.
“She got along well with everyone in the class,” Long said. “Everyone liked her.”
She said her heart broke when she learned that the 13-year-old was the victim found dead in the county earlier this month.
"She didn't deserve anything that could have happened," Long said.
A Huntsville City Schools spokesman told WAFF that school administrators and officials were saddened to learn of Lopez's death.
"We extend our heartfelt sympathy to the family and will keep them in our thoughts and prayers," Keith Ward said.
The case was first described as a homicide investigation a week after the discovery of the body, when the honor roll student was positively identified. Mendoza, who was Lopez's legal guardian, was still missing and believed to be in danger, Sheriff's Office officials said.
The case moved quickly at that point, with Aguilar and Palomino being developed as suspects overnight. Both men, who were acquaintances of Mendoza and her granddaughter, were subsequently taken into custody at the home they shared.
Palomino was initially arrested for possession of methamphetamine, WAFF reported. Both men were interviewed separately, at which time detectives developed enough probable cause to arrest them in Lopez's killing.
Leads in the investigation led detectives to Moon Cemetery, where the second body was found, according to a news release issued Friday. The cemetery is about 2½ miles from the wooded area where Lopez's body was found.
"There is reason to believe that the remains are those of Oralia Mendoza, the missing guardian/grandmother of Mariah Lopez," the release said. "However, positive identification will have to be made by the Department of Forensic Sciences."
The news release did not indicate if either of the men led investigators to the body’s location.
Shaw told WAFF that all indications were that the body was that of Mendoza.
"It's a sad update, but it's moving closer as to when we can make a positive identification (and) we can give this family some closure as to what happened, how it happened and what exactly occurred in this case," Shaw said.
The spokesman credited the community with moving the investigation forward.
"For a murder where there were no indications, no witnesses, nothing to lean on when we began with it, the Hispanic community, the partners, the media, we've been able to do a phenomenal thing in just a little over seven days by coming to the arrests of two individuals," Shaw said.
Palomino and Aguilar are both being held without bond in the Madison County jail. Aguilar is also being held for U.S. Immigration and Customs Enforcement.