UPDATE December 14, 2018:

Judge Tracy Hudson sentenced Ronald Francis Dorsey to two consecutive life sentences for the murders of Lizeth Lopez, 36, and Erica Hickson, 37, the Prince William Times reports.

Dorsey pleaded guilty to two counts of first-degree murder in July 2017.

November 28, 2016:

Surveillance video shows University of Maryland student Lizeth Lopez just weeks away from fulfilling a lifelong dream of being a college graduate. The video marks the last time Lopez was seen alive.

At the age of 36, Lizeth Lopez went back to college for a degree in criminology. She had a fascination with criminal behavior.

Prince William County Police Sgt. Jonathan Perok says that on the night of April 17, Lizeth Lopez was working a late shift as a youth counselor at an apartment complex in Maryland. At around 9 p.m. she took a routine break to run an errand.

"She goes to the CVS store, which is about two miles away from where her work is," said Perok.

A security camera captures her entering and later leaving the drug store. Each times she's alone.

"She casually walks in, casually leaves with the few items that she had purchased, and that is the last time we have visual confirmation of her anywhere in the county," said Sgt. Perok.

Her family fears Lopez has been abducted, and cops are suspicious too. Police and volunteers canvass the neighborhood. They find her car in the parking lot where she was working, but no clues inside.

"We're exploring different theories different scenarios we think may have happened," said Perok.

After 10 days of frustration searching, cops fear Lopez will end up another missing-person cold case, until a nosey dog makes a grisly discovery.

"It was a neighbor that lived in that area and they couldn't figure out why the dog was barking, maybe they thought the dog had to go to the bathroom or something like that, so they took the dog out and that's when she was discovered," said Perok.

Neighbors could actually see Lopez's naked body stuffed inside a drainage ditch. Police say that without a doubt, Lopez was murdered by a cold-blooded killer.

"Where she was found is not a usual spot for anyone to routinely go, so obviously she was either placed there or left there, so we're trying to really kind of narrow down, figure out what happened and when she died," said Sgt. Perok.

Investigators are running out of clues.

Then, almost four months after Lizeth Lopez disappeared, another youth counselor vanishes. Erica Hickson worked together with Lizeth Lopez at the same nonprofit program. Tragically, Hickson's family doesn't have to wait long for answers: The next day police find her body in a wooded area.

After questioning other co-workers, cops arrest Ronald Dorsey Jr., 19, and charge him with both murders. Police tell Crime Watch Daily he was a resident at the youth program, and claim Lopez and Hickson had both counseled him. Dorsey has yet to enter a plea, but police claim he killed two women who did nothing but try to help him.

If you have information about these cases, contact the Prince William County Police Department at (703) 792-6500.