Bucks County prosecutors on Friday charged a Doylestown man with falsely reporting a carjacking Monday night, diverting police attention and resources from the manhunt for alleged mass killer Bradley Stone.

Luke Sanderlin, 34, faces charges of risking a catastrophe, recklessly endangering another person, and making false reports to law enforcement, Bucks County District Attorney David Heckler said Friday.

"We contend that he performed an enormous hoax that cost taxpayers a lot of money," Heckler said at a news conference Friday night. "This is terrible conduct. This is unacceptable conduct."

At the time of the carjacking report, Heckler said, people were afraid that a killer was "roaming across the countryside."

Heckler said that Sanderlin knew about the manhunt for Stone, who was being sought in the slayings of six people early Monday, when he falsely reported being attacked by a knife-wielding man who looked like Stone near Burpee Road and Route 202. Police, K-9 units, and helicopters soon flooded the area, and satellite media trucks were not far behind.

Sanderlin told authorities that the man tried to take his car keys and that his pit bull attacked the man before Sanderlin chased him off with gunfire, Heckler said.

Officers were suspicious, Heckler said, but an associate of Stone's lived in a nearby apartment building, and the claim was treated as legitimate. Police calculated that Stone could have traveled five miles in the time after the supposed attack, reported at 7:09 p.m., and searched an area within that radius.

Investigators later determined that Sanderlin was not around his car at the time of the reported attack, Heckler said. A police affidavit said that there was no evidence that anyone else was in the area at that time, and that although witnesses reported hearing gunshots, none heard voices or a barking dog, and none saw anyone fleeing the scene.

Authorities said they believed Sanderlin has no criminal history. He legally owned the gun he allegedly fired in the incident, Heckler said.

Nobody answered the door at Sanderlin's residence when a reporter knocked Friday night.

Heckler said Sanderlin recently tried to raise money for treating an alleged neurological disease but had little success.

Sanderlin had set up a website to bring in money and had scheduled a beef-and-beer fund-raiser for March in Philadelphia, Heckler said. His wife reportedly told a neighbor that fund-raising was not going well and that "if things didn't pick up, they might have to invent something like a bout of cancer," Heckler said.

"He seized an opportunity and he caused an enormous amount of expense, anguish, anxiety, and some very real risks, not the least of which, he discharged his firearm three times in an area that is substantially residential in nature," Heckler said.

The District Attorney's Office is still tallying the cost and manpower expended in the search for Sanderlin's phantom assailant, Heckler said.

Sanderlin was arraigned before District Judge Mark Douple, and bail was set at $250,000 surety or $25,000 cash.

Authorities say Stone killed his ex-wife and five members of her family early Monday in a rampage that spanned three Montgomery County towns. He was found dead Tuesday in a patch of woods in Pennsburg.

Still unclear is how Stone and each of his victims died. He used a gun but wielded some sort of knife in the killings, according to an affidavit released this week. And prosecutors have said his body was found in the woods with medicine containers, a machete, and a double-edged ax, although medical examiners have said injuries did not kill him. Montgomery County officials offered no new information Friday on their investigation.

cpalmer@phillynews.com 609-217-8305 @cs_palmer