ROANOKE, Va. -

As we enter into a new year, there are still a number of questions left unanswered regarding some of 2013's biggest criminal cases.

The death of Jamisha Gilbert is a prime example. The 18-year-old was reported missing in early December. Days later, investigators found her body in an field near Concord Turnpike in Lynchburg and so far, no one has been arrested and charged in connection to her death.

Investigators tell WDBJ 7 they're still waiting on toxicology reports, among other things, before they can move forward in the case.

Crucial pieces of evidence can take weeks or even months to get back in some cases.

"The workload in toxicology from when I got here 13 years ago was fairly small," said toxicologst James Kuhlman.

Kuhlman is the forensic toxicologist supervisor at the Virginia Department of Forensic Science Western Lab.

Kuhlman said there's never been a slow or easy day in the forensic lab, but these days, it's busier than ever.

New legal requirements, new drugs and an increase in drug abuse has Roanoke analysts working overtime looking at blood samples and other biological fluids.

"That can take a significant amount of time and of course, we don't know what we will run into when they ask for that."

Once any piece of evidence is dropped off at the Roanoke lab, a very long and meticulous process soon begins.

"The blood has to be removed from the blood through a chemical process, it has to be purified, concentrated and then put into an instrument that will identify the drug," he said.

But that's only the beginning.

The samples are then reviewed by another forensic team and examined for a second time before given a final stamp of approval.

According to Kuhlman, there are fewer than ten people in the Roanoke toxicology lab. His teams processes an average of 200 cases a month and that doesn't include other tasks they have to do with the job.

"We spend a significant amount of time talking to attorneys, police officers, the medical examiners, answering questions," he said.

The toxicologists also spend much of their time traveling every month to testify in court so the work they do inside the lab holds up inside a courtroom.

The Western lab is responsible for processing requests from more than 20 counties in southwest and western Virginia.