LOUISVILLE, Ky. (WDRB) -- Among the graves at River Valley Cemetery is a murder mystery.

Police say there are seven unidentified bodies in Jefferson County -- and at least two are murders. Police are hoping the public can help solve the cases.

"So the longer it goes, the worse our chances," said Medical Examiner Dr. Amy Burrows-Beckham.

"Juan Doe"

Students helped pay for the grave of a man they call "Juan Doe" -- instead of John Doe. Police still don't know who the Hispanic man is, but he was murdered in 2009.

"I can imagine what the families are going through," said Burrows-Beckham. "If my dog goes missing, I'm not going to sleep until I found my dog. I can't imagine what people missing their children, their spouses or their mothers and fathers are going through." 

In the autopsy room, LMPD Detective Anne Hogan, of the Major Crimes Division and Mission Persons Unit, and Burrows-Beckham are going over the cases trying to name the seven unidentified bodies in Jefferson County. In that room, hours are spent looking for more clues. 

Even with his picture and five people serving time for killing him, Juan Doe's real name is unknown.

"His front teeth were a partial plate, so if that stands out to anybody..." people should call police, said Det. Hogan.

2005 murder

Shively Police are still investigating a murder from 2005. They're hoping someone recognizes a woman between 20 and 40 years old.

"We're not sure what her hair is, what her eye color was, it's just a general overall to what her face shape may have been," said Burrows-Beckham.

Investigators say her bones were found under flooring while construction crews were clearing a site on 7th Street Road. Police say evidence shows her hands were tied and she was likely strangled.

Burrows-Beckham says as more time goes by, these cases can be harder to solve.

"People are dying, so the people who have might know who she was or what happened in that area of town, might be dead," she said.

1998 victim

Back in 1998, a man wearing white tennis shoes was found fully clothed on the shores of the Ohio River, east of the McAlpine Locks and Dam.

"He had no obvious trauma," Burrows-Beckham said. "We think he may have drowned."

1997 "Georg" tattoo

In a case from 1997, the identifying clue is a tattoo.

"We call him 'George,'" Burrows-Beckham said. "It was a decomposed nude male found on the banks of the Ohio. Unfortunately, what happens when they decompose, the top layer of skin sloughs off."

His left arm has the word "Georg" tattooed on it. Burrows-Beckham think there was also an, "E" but that's hard to see. Investigators think he's between 20 and 50 years old.

Burrows-Beckham says there are some difficulties when bodies are found in a river.

"If they are not found quickly -- especially in the warm months -- they will start to decompose, especially when you pull them out of the water," she said, adding that, "they're going to get bloated, their skin color is going to change."

She says that makes it difficult to determine the body's race.

2017: Outer Loop human remains

In February of this year, human remains were found on the Outer Loop at I-65 in a grassy area. The man's skeletonized body had dreadlocks several inches long, with some gray in them, and he was wearing a necklace with an "ankh" symbol, which is a design resembling a cross, but it has a loop on top. It was used in ancient Egypt as a symbol of life. Police think he was possibly African-American, but investigators say it's hard to tell his exact race because of the condition of the body.

2016: Body found on plywood

In July of 2016 on Minor Lane, a man's body was found lying on a piece of plywood. He was wearing gray mountain gear boots. Investigators say he's a white man with possibly red hair, between 29 and 48 years old.

When asked if the 2016 and 2017 cases are suspicious, Hogan says,  "At this point, those are both open cases. We really don't want to say."

2004 suicide

For the seventh unsolved case, police say a man killed himself on Sept. 9, 2004, in a home in Louisville's south end in the 5100 block of Roederer Drive. Investigators say he had been staying with people in the home that he worked with. But still, police don't know who he is. They say he's between 35 and 40 years old, and think he's Hispanic or Caucasian.

"He called himself Jose," Burrows-Beckham said, adding that he said he was from the Chicago area, had family in Chicago, and may have been wanted by the police in Chicago. However, he didn't really tell anyone more about himself or his family. He also wore a chain with the letter "M." 

All of the cases are among the thousands in NamUs, a website for the the National Missing and Unidentified Persons System. Police are asking people to look at the site, to see if they know any of the missing people or unidentified bodies. You'll find detailed information and images of evidence from each of these cases. 

In Jefferson County, LMPD says 1,924 reports were taken this year for missing persons. There are 210 open cases and 27 are considered to be long-term missing persons cases.

Police say they have hope they'll find out who the unidentified bodies were. Kentucky's oldest case, one from 1969, was recently solved.

"We don't ever forget," Hogan said. "We never close a case until they are found."

Investigators say fingerprints are the quickest and easiest way to identify people, but when bodies decompose, sometimes the fingerprints are no longer available. That's why they also rely on dental records.

"We will take everything we need -- DNA, fingerprints, get the dentals done by our forensic dentists, take full-body x-rays -- because we don't have room to store everybody," Burrows-Beckham said.

She says some of the bodies have been buried after people raised money for public burials. She says some of the more recent remains are at a medical examiner's office, or an anthropologist's office. 

Anyone with information on the Louisville cases can call (502) 574-LMPD and you can call Shively Police at (502) 448-6181 with any information on the Shively case.

Burrows-Beckham reminds people to keep fingerprints of your family members and let them know what dentist you go to. That makes it easier to identify you, in case something happens. 

Copyright 2017 WDRB News. All rights reserved.