Here's a rundown of the unsolved homicide cases in Hyattsville:

Case #1 - March 26, 2008 - Three people were shot around 8:30 p.m. Two of them died. The victims were walking toward their car on Manorwood Drive. There were three unknown suspects. Case not closed.

Case #2 - October 22, 2008 – Twenty-year-old Pedro Luis Hernandez, a graduate of Archbishop Carroll High School, was shot outside his home at the corner of Gallatin Street and 42nd Place. A vigil was held at Robert King Memorial Park eight days later to remember the young man and a park bench was later dedicated to him. Case still open.

Case #3 - September 16, 2010 - Northwestern High School student Erlin Alexis Ronero-Ramirez was killed on Nicholson Street in the afternoon. He was with an acquaintance who was not hurt. Case currently under investigation.

These are three examples of unsolved cases currently active with Prince George's County Police Department's Homicide Unit. According to the unit, they exhausted their leads on the Manorwood Drive case but they received a tip regarding the Hernandez case. They are actively investigating the Northwestern High School student case. The cases are unrelated.

The county's homicide unit handles homicides in Hyattsville. The city's police department usually knows very little about the status of homicide cases once they are handed over to the county.

Do individual municipal police departments want to be more involved with homicide cases in their community?

Lieutenant Mark Roski of the Hyattsville Police Department says yes and no.

"I would love to have our own homicide unit," said Roski. "But we would need the equipment and personnel – and we're just not big enough."

The Prince George's County Police Department is the 33rd largest police department in the country. The homicide unit has 33 experienced homicide investigators and its own DNA lab. The department also has a repeat offender unit and a gang unit.

Despite these unsolved cases and numerous other ones in the area homicide unit commander Lt. W. Rayle said the number of murders in the county has actually gone down over the past few years. Since January there have been 75 murders. Last year in total the county had around 130 homicide cases. The highest recorded number of homicides was in 2005 with 155 cases.

What's the reason for the decrease?

Rayle says it's the county's growing relationship with communities.

"I believe the decrease in numbers is from our personal relationship and partnership with the community, " said Rayle. "Trends are also down almost everywhere."

In November 2008, Roberto Hylton became county police chief. Ever since his election, he has encouraged community-orientated policing and incorporated more programs with residents, Rayle said.

In January 2009, a cold case squad was created in the homicide unit to investigate unsolved cases that are five years or older. The squad includes a team of experienced investigators who recently closed a case that dated back to 1968. A case is not closed until it is officially solved and it is considered "cold" when all of its leads have been exhausted.

Roski said the county's homicide unit is doing excellent work on the unsolved homicide cases in his community.

"They work really hard at solving every case," he said.

If you have tips regarding the unsolved cases mentioned, please call Prince George's County Crime Solvers tip line at the toll free number 866-411-TIPS (8477).