Updated

Police on late Friday detained a person of interest in the stabbings of three Los Angeles-area homeless people in recent weeks, a man they say goes by a name signed on "death warrants" found with the wounded victims.

Courtney Anthony Robinson was taken into custody in the Hollywood area and was being questioned by detectives. Police have not called him a suspect in the case.

They previously described him as a possibly homeless man from Santa Barbara who also goes by David Ben Keyes, a name written on notes left at all three stabbing scenes that the writer called "death warrants."

One victim in Santa Monica and two in Los Angeles were stabbed in the back as they slept. The first stabbing occurred July 3 in downtown Los Angeles, the only incident where a witness saw a suspect fleeing; The second on Tuesday targeted a man as he slept on a bus bench in Santa Monica. The most recent was on Thursday, when a woman was stabbed in Hollywood.

The three victims, all in their 50s, survived.

Earlier Friday, police and advocates urged homeless people to seek safety in shelters as news spread of an at-large serial stabber. But they faced the challenge that many street dwellers like being alone because they feel it's less risky or simply because they can't cope with people due to mental illness.

Charles Barfield, living on the streets for the past five years, arms himself with a pocketknife and beds down in a downtown doorway every night, making sure no one's nearby.

"People might look normal, but they do weird ... things," said the ponytailed 58-year-old who sells loose cigarettes for a quarter.

With robberies, assaults or even rapes frequently occurring on the streets and in shelters, many homeless people have found that survival comes down to finding places where no one can see them.

But advocates for the homeless say that's also what makes them easy marks for criminals looking for victims in general or homeless people specifically.

"People on the street know it's dangerous, but many people want to be on their own," said Herb Smith, president and chief executive of the Los Angeles Mission in Skid Row in downtown Los Angeles. "They're not socialized. It's part of their condition."

Warnings about the hazards of sleeping on the street were stepped up as police continued to hunt the perpetrator. Shelters in downtown Los Angeles' Skid Row, the nation's densest concentration of homeless where more than 1,000 people sleep on sidewalks nightly, were taking the threat seriously.

"We're all on high alert," said Georgia Berkovich, spokeswoman for the Midnight Mission, where an extra room was being prepared in case more people turned up for beds Friday.

The mission distributed news stories about the stabbings and photos of Robinson to staff and security guards, while nearby Union Rescue Mission posted fliers around its premises, made an announcement during lunch and spread warnings along with bottled water at its mid-afternoon "water walk."

If people don't want to come into shelters, they are being urged to form small groups to sleep on the streets at night.

Men are often more challenging to reach than women, who must deal with the added threat of sexual assault and seek shelters or buddy up for that reason, advocates said.

"The men tend to be very much loners. They find it much more difficult to congregate," Smith said.

Skid Row residents took the news of a serial stabber in stride, saying they are already used to taking precautions to protect themselves from the fistfights, knifings and sexual assaults that commonly occur in the area.

"It happens all the time and in the day," said Theresa Esogbue, who said she had been raped and mugged twice.

Esogbue, who said she was in her 40s, said she sleeps in shelters and seeks out the company of other women, but has learned to be wary of everyone.

"I keep to myself," she said. "I don't have a lot of friends here."

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