The man who was fatally stabbed while camping on the Appalachian Trail in southwestern Virginia early Saturday was identified by federal authorities Tuesday as Ronald S. Sanchez Jr., 43, of Oklahoma.

Sanchez, an unidentified woman and two other people were hiking the trail on Friday when they set up camp in Wythe County, the FBI said. Sometime after 1 a.m., their campsite was invaded by a man who spoke to them from outside their tents and threatened to set the tents on fire, according to an FBI affidavit filed Monday.

The four campers began to pack up, and when the man wielded a long knife, two of them fled into the woods and escaped, the FBI said. The man then returned, argued with Sanchez and then fatally stabbed him, authorities said.

A woman who was with Sanchez fled but the attacker caught her and stabbed her repeatedly, the FBI affidavit states. She played dead and fled into a neighboring county when the attacker left.

The FBI said Sanchez had managed to activate an emergency help signal, and local sheriff’s deputies began searching for him. Shortly after 6 a.m., the deputies followed a dog who apparently belonged to the attacker, and the dog led them to Sanchez’s campsite.

This file photo shows the Appalachian Trail and the rural nature of the trail near the scene of the fatal attack on Saturday, May 11, 2019. This is about one mile from where the attack occurred. (Appalachian Trail Conservancy)

Sanchez was found dead, with a 20-inch knife near his body, FBI Special Agent Micah J. Childers wrote in the affidavit.

James L. Jordan, 30, was also at the campsite with blood on his clothes, according to Childers’s affidavit. Jordan, of Yarmouth, Mass., was arrested and charged with murder and assault with intent to commit murder. On Monday, he was ordered detained pending a psychiatric evaluation.

No information was immediately available on Sanchez.

Arelis R. Hernández contributed to this report.