https://www.theverge.com/2018/6/3/17418698/daniel-beckwitt-askia-khafra-bethesda

In September, 21-year-old Askia Khafra was found dead after a house fire in a suburban Bethesda home belonging to security researcher Daniel Beckwitt. Now Beckwitt has been charged with murder in connection with Khafra’s death. Prosecutors say Khafra had been hired to construct an intricate network of tunnels below Beckwitt’s home, and that his death resulted from unsafe working conditions.

According to court documents, the tunnels were dug 20 feet below the basement of the home, spanning as far as 200 feet. The tunnels were constructed under extreme secrecy, with local permitting agencies unaware of the full extent of the construction. Khafra arrived at the work site wearing black-out glasses to prevent him from knowing its location; throughout the construction, he believed the house was in Virginia.