Two cold cases, both decades old and both involving African-American girls who disappeared in the 1970s, are starting to heat up in Central Florida.

In 1977, just about seven months after Nancy Grace Daniel was last seen alive, her remains were found near Lake Mann. Around that same time, the remains of another African-American girl, who remains unidentified, were found in the same area near the lake.

Daniel's remains were not identified until May 2014, and the second victim remains known only as "Jane Doe."

Investigators believe both deaths were homicides, and now, they hope the public can help lead them to the person who killed the two girls.

Daniel, 14, was last seen alive on Sept. 6, 1976, in the Parramore neighborhood, near Parramore Avenue and Anderson Street.

Her cousin, Eugenia Oliver, was with her right before she disappeared.

"She was a young girl, beautiful," recalled Oliver. "Just disappeared overnight."

Daniel was last seen getting into a car described as having a black top and red bottom. Her brother, Willie, said he believes she got in the car with a stranger.

Willie Daniel said he never really thought she was murdered — until he got a call last month.

"I never thought she was dead, until this came up," said Willie.

Detectives reopened Daniel's case last year as part of a project with the National Center for Missing and Exploited Children. Orange County Sheriff Jerry Demings said it took so long to identify the remains, because the body was found in unincorporated Orange County, but the missing person report was filed with the city of Orlando.

Back then, Demings explained, jurisdictions didn't communicate with each other as well.

"Due to the severe decomposition and lack of technology, both sets of remains were unidentified for decades," Demings said.

The remains of the second victim were actually found first, two months before Daniel's. Detectives hope the public can identify her — and whoever is responsible for both deaths.

"Please, come forward, because you can't run forever," Willie Daniel pleaded. "This is out now. It wasn't out, but the whole world knows this now."

Nancy's story is not uncommon. Investigators say over 40,000 bodies sit unidentified in medical examiners' offices across the country.

CrimeLine is offering a $5,000 reward for any information that could lead them to an arrest in this case. You can leave an anonymous tip by calling (800) 423-TIPS.