When Geoffrey Farrar was found lying on the trail with massive head trauma at Maryland's Carderock Recreation Area three days after Christmas, authorities initially believed the veteran climber had taken a precipitous fall.
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Nearly three weeks later, David DiPaolo, 31, has been charged with manslaughter in the death of his mentor, Farrar, 69, who authorities said was fatally bludgeoned with a claw hammer after the two men had an argument.
DiPaolo, who was arrested in Glens Falls, N.Y., on Jan. 8, told authorities he acted in self-defense after he said Farrar wrestled him to the ground and choked him to the point he was losing consciousness, according to a federal complaint. The case is being handled by federal prosecutors because Carderock is a national park.
"DiPaolo then found a silver-colored claw hammer with a red handle on the ground nearby. With his right hand, DiPaolo used the claw hammer to strike the victim in the head," the complaint said.
Farrar, who was found bleeding from the head, was taken to Suburban Hospital in Bethesda, Md., according to an obituary, and he died there later that day from his injuries.
The case has sent shockwaves through the tight-knit community of climbers who often saw Farrar and DiPaolo adventuring outdoors together.
Farrar was such a regular at the climbing spot that he was known by people in the community as "Carderock Geoff," a guy always ready with a smile and a story for fellow climbers.
If there was a face of Carderock, it was Farrar, according to online posts, but DiPaolo, described as a long-haired bohemian who Farrar called "Little Dave," came a close second.
"I know that Geoff and Dave had climbed together because I had exchanged stories with Geoff about Dave many times," climber William Kelley wrote on the Mountain Project forum. "I was shocked to hear of Geoff's passing and am now even more shocked by hearing of Dave's alleged involvement."
Authorities said witnesses, including one who had known both men for more than 20 years, saw them arguing in the Carderock parking lot on Dec. 28.
When two witnesses then went to the top of the rock face to secure their ropes, they didn't see anyone, according to the complaint. They then walked to the bottom and saw DiPaolo running up the trail in a green hooded sweatshirt, according to the documents.
One of the witnesses called out DiPaolo's name, the complaint said, but he kept on running and did not respond.
An examination of Farrar's body, conducted one day after he died, found "numerous open fractures to the skull" and lacerations on the backs of his hands, according to the complaint.
"No other wounds consistent with a fall were discovered during the examination, nor did the victim suffer from any other injuries to any part of the body besides the skull and hands," the complaint said.
In a written statement, authorities said DiPaolo, who has not yet entered a plea, expressed remorse at his friend's death.
"I'm sorry this happened," he wrote, according to the complaint. "I didn't want it to happen. I didn't know it was going to happen."
Neither Farrar's family nor DiPaolo’s family could be reached for comment.