Beckwitt is expected to make his first appearance as soon as this week in a Montgomery County, Maryland courtroom. He was arrested at the weekend in Fairfax County, Virginia, and has been held there.
New details in the case are spelled out in an affidavit that Montgomery detectives filed to secure charges against Beckwitt.
The document describes the extent of the tunnel complex, which was at least 6m deep and approximately 60m in length. Still a mystery is why Beckwitt wanted the tunnels and how he intended to use them.
But the affidavit describes efforts Beckwitt took to keep his project secret.
He allegedly took a rental car to pick up Khafra at his home in Silver Spring, Maryland, drove him to Manassas, Virginia, had him place "darkened, blackout glasses" on his face that kept him from seeing and told him he was taking him to a job site in Virginia.
Instead, according to detectives, Beckwitt drove Khafra to his home in Bethesda, led him to the basement and only then allowed him to remove the blackout glasses.
Lawyers who represent Beckwitt in a lawsuit about the tunnels, filed by Montgomery County, could not be reached for comment. It was not clear whether he has yet retained a lawyer in the criminal case.
Police also charged Beckwitt with a lesser crime, involuntary manslaughter, which carries a sentence of 10 years, court records state.
According to the affidavit in the criminal case, Montgomery firefighters and police officers went to the Bethesda home on September 10 for a call about a house fire. They found fire in the basement and Beckwitt outside the home. He told them that someone was in the basement.
It was there, according to the affidavit, that investigators found Khafra's body.
"Fire investigators discovered a hole in the concrete basement floor, which led to an underground tunnel complex underneath the basement," Montgomery detective Michele Smith wrote in the affidavit, signed on May. 25. "The entrance shaft dropped down approximately 20 feet, where the tunnels branched out approximately 200 feet in length."
Detectives spoke to Beckwitt, who told them about renting a car, picking up Khafra in Silver Spring and taking him back to Bethesda via the circuitous route through Virginia.
According to the affidavit, detectives built much of their depraved-heart-murder case based on two significant conditions in the house. The first involved "hoarding" conditions that would have made it difficult for anyone to escape quickly.
Smith wrote that investigators found "immense piles of garbage and discarded items strewn throughout the entire home."
She said there were "narrow, maze-like pathways throughout, which significantly prevented normal ease of movement within the home."
Authorities also alleged that the tunnel complex required "substantial electrical needs" that "were served by a haphazard, daisy-chain of extension cords and plug extenders that created a substantial risk of fire."
