In fierce August heat, Los Angeles County sheriff's deputies expanded their search Thursday for a missing Topanga man who, in a final mysterious phone call to a friend, had reported being chased along Topanga Creek.
Sheriff's investigators, however, downplayed one widely reported theory behind the disappearance of Christian Julian Irwin -- that he was the victim of a Nigerian Internet fraud scheme that had turned violent.
Irwin, 48, had been drawn into such a scam, they said, but investigators had little evidence to connect that with his fate.
They said another possibility is that confusion -- perhaps related to some unknown medical problem -- caused Irwin's sudden, baffling flight from his house in the dead of night, barefoot and in fear for his life, to hide in the rough creek gorge.
They said they are afraid he may have fallen or injured himself.
"We aren't going to disregard any possibility," said Capt. Ray Peavy of the sheriff's homicide unit. "Did foul play occur? It's very possible. And it's possible it didn't. He obviously felt threatened. Whether that was real or imagined is impossible for us to know."
More important now, Peavy said, is finding Irwin alive as soon as possible.
"We aren't focusing on any particular reason for why he ran away. He's gone, and we are trying to find him. Our main concern is that he is hurt and may be out there in the heat and heavy brush," Peavy said.
Teams of about 30 deputies raked through sweltering brush for hours Thursday without success, trying to follow Irwin's suspected path along the stream that coils through the Santa Monica Mountains to the Pacific. The searchers included divers who plunged into 6-foot-deep pools along the creek bed to see whether Irwin might have tumbled in and drowned. Wrapping up the day's search in the late afternoon, deputies promised to resume this morning.
Each day that passes, Peavy said, worsens Irwin's chances for survival in the dense chaparral.
Irwin's relatives, meanwhile, said they were dubious about the medical theory, adding that Irwin was scrupulously health conscious and had no history of mental illness, substance abuse, strokes or any other condition that might so drastically alter his judgment. Moreover, they said, he had behaved much as usual when seen by friends just before Sunday's incident.
A large group of friends and family were keeping vigil at Irwin's Topanga Canyon home Thursday, as they have all week. Earlier, police had warned them off the hillsides, saying the uneven terrain was too dangerous for untrained search teams.
New details of the case offered Thursday shed little light on the incident, or the circumstances that led up to Irwin's wild race down the steep incline behind his house in the early hours of Sunday.
Friends and family believe Irwin may have felt threatened by the Internet scam artists with whom he had become involved. The scam, typical of many on the Web, took the form of an e-mail offering potential victims a cut of the assets of a wealthy person who died in Nigeria if they agreed to help transfer the funds out of the country, they reported.
Irwin had told his friend Fortunato Procopio of his interest in the e-mail months ago, but had not mentioned that he felt threatened. Procopio had pooh-poohed the idea, telling Irwin to disregard the e-mail and that such Internet appeals could only be scams.
But other acquaintances reported that Irwin's involvement in the scheme grew and may have escalated to telephone calls, even a plan by Irwin to travel overseas at someone else's expense. But Irwin balked when the scam artists sent him a $50,000 check -- a gross overpayment of what they had promised him -- then demanded repayment, according to sheriff's investigators.
He returned the check to the bank, and it was later revealed to have been forged.
Such schemes -- a variation on older scams once conducted through regular mail -- have taken so many forms and become so common that federal law enforcement agencies no longer classify them as strictly "Nigerian."
"It's more just general Internet fraud," said Tom Mazur, a spokesman for the Secret Service. Loose criminal networks perpetrate the scams all over the country, but they are not typically linked to any kind of violence, he added.
Investigators have confirmed the following account: In final, frightened cellphone calls to Procopio before he disappeared about 3:45 a.m. Sunday, Irwin reported that people were chasing him and said his pursuers possibly had dogs and cars.
He spoke in a hushed, breathless voice, offering only cryptic clues about who was chasing him. He said his pursuers may have been people drawn to him by "the money," or "the e-mail," or were possibly connected to his father, who died in March.
Alarmed, Procopio raced toward Topanga from Venice with girlfriend Melinda Ahrens by his side to rescue Irwin.