A network of “unsupported and unauthorized” underground tunnels discovered under a Bethesda home after a deadly fire last fall still have not been repaired, leaving the area with conditions “dangerous and hazardous to human life and the public welfare,” according to a lawsuit Montgomery County brought against two men connected with the home.

The suit, filed Friday in Montgomery County Circuit Court, seeks to require the home’s owner, David Beckwitt of Burke, Va., and Daniel Beckwitt of Bethesda — described as the creator of the tunnels — to comply with numerous requests from county departments to demolish the Danbury Road home and fill in the tunnels.

“We filed a complaint because the county believes, based on what we know, that the structural integrity of the house has been undermined by the tunnels,” county spokesman Patrick Lacefield said Monday. “It has to be remediated so the property can be in a stable situation and we can also figure out precisely where the tunnels are and remediate them as well.”

The tunnels, coupled with “hoarding conditions” in the home, were discovered after a Sept. 10 fire at the property. The body of 21-year-old Askia Khafra was found in the house after the fire. The victim was discovered in the basement but not in any of the tunnels, according to Scott Goldstein, chief of Montgomery County Fire and Rescue Service.

The excavations extend beyond the home into the public right of way in front of the house and “likely” at least one other property, according to the suit.

County fire and rescue personnel had made limited entry into the tunnels but were restricted from a fuller exploration because the excavations were “congested and in some cases unsupported,” Lacefield said.

Daniel Beckwitt did not respond to a request for comment Monday, and a man who answered the phone at a number listed for David Beckwitt would only say that he was not available before hanging up. A Baltimore attorney listed as representing the Beckwitts did not respond Monday to a request for ­comment.

Montgomery County detectives continue to investigate the circumstances of the death in the house, said Capt. Darren Francke, head of the county’s major crimes division. No criminal charges have been filed in the case, Francke said.

The Maryland Office of the Chief Medical Examiner determined the cause of Khafra’s death to be smoke inhalation and thermal injuries, Francke said. The manner of death remains under investigation, he said.

Khafra’s mother, Claudia Khafra, said Monday she was deep in grief over her son’s death.

She said her son was a budding entrepreneur who was focused on getting his fledgling business off the ground when he died. She said Daniel Beckwitt had been a friend of her son, but she didn’t know about activities at the house.

The home remained fenced off Monday, with yellow caution tape draped over a chain-link fence surrounding the property. Bright orange stickers bearing the word “UNSAFE” were stuck on the front and side doors of the property, debris could be seen through broken windows, and a blue tarp covered part of the roof in the back of the home.

Nancy Abeles, a committee member of the Bethesda Crest homeowner’s association and passes the house on her morning walks through the neighborhood called the situation “extremely creepy.”

“Everybody wants to know, what the heck were they doing in there?” she said.

Dan Morse and Eddy Palanzo contributed to this report.