Trial begins Thursday for Randy Allen Taylor, the man accused of killing Nelson County teenager Alexis Murphy.

It's been a long investigation - with more questions than answers, especially since there is still no sign of Alexis.

Alexis Murphy left her home in Shipman Saturday, August 3, reportedly heading toward Lynchburg. Surveillance video shows her at the Liberty gas station in Lovingston around 7:15 that night. That was the last time she was seen.

No sign of the missing teen sparked pleas from investigators, the FBI, and Murphy’s family.

Authorities arrested Taylor, 48, on Sunday, August 11, and charged him with felony abduction in relation to the case. He was charged with first-degree murder in relation to the case on January 6.

There is still no body or no sign of Alexis – and with a gag order in place on the case, it is unclear what evidence investigators have against Taylor.

One big question remains - how can someone be charged with murder without a body?

Charging someone with murder without a body is not something you see very often. In fact, this will only be the third ever trial of its kind in Virginia. NBC29 sat down with criminal defense attorney Bonnie Lepold who spoke about the challenges that may come up along the way.

"Right now, all they have is a missing person. That's a huge leap that the prosecution is asking potential jurors to make,” said Lepold.

The fact that there is no body presents a huge leap for the jury and an uphill battle for the commonwealth's attorney to convict Taylor of first-degree murder.

"Certainly it's a hurdle that doesn't exist when there is a body,” said Lepold.

Lepold says without Alexis' body, it may be hard to prove cause of death or that a death has even occurred.

"What they have to establish then is well, how to we get to a missing person to prove beyond a reasonable doubt that in fact there is a death,” said Lepold. "I imagine that the evidence that would be presented is going to be largely circumstantial.”

The case is similar to the only two other no-body murder cases in Virginia - the disappearance of Katie Worsky from Charlottesville and Gina Hall from Blacksburg, both more than 30 years ago.

But whether it is circumstantial evidence or something else the prosecution has up its sleeve, it will have to tie Alexis and Taylor together.

"There could also be some forensic evidence. For instance there may be blood evidence, DNA evidence located somewhere in a place where the suspect had been staying, a vehicle that had been used by him, things like that,” said Lepold.

Taylor’s trial is set to begin in Nelson County Circuit Court at 9:30 a.m. Thursday. The trial is scheduled to last two weeks.

Click here for more information on the case. Follow NBC29 on Twitter @NBC29 for updates from the trial.