In 1997, the Coppell Realtor was attacked and left for dead while showing a home.

"We're all talking about this" latest assault on a home sales agent, Ms. Malone said. "There are people out there with bad intentions."

"The only thing you can do is go with your gut feeling, and if it doesn't feel right, get out of there," she said.

Between 1982 and 2000, more than 200 U.S. real estate agents were killed on the job, according to a safety report published by the Kentucky Real Estate Commission. Untold other agents were raped or mugged.

On Saturday, prospective buyers who stopped to tour a McKinney model home found Sarah Anne Walker's body. She had been stabbed more than two dozen times. Police are sifting through clues to find her assailant.

In 2002, at least four sales agents were robbed at gunpoint while showing homes in North Dallas.

And not all attacks get publicity.

In an industry that depends on one-on-one contact, sales agents know that they must be wary of the wrong kind of person.

"If only we knew what an attacker looks like – that's the problem," said Sherryl Wesson, an office manager for Dallas-based Ebby Halliday Realtors. "You have to be on guard all the time."

To keep sales agents safe, Ms. Wesson said her firm asks prospects who want to see a home to meet at the agent's office and provide identification. And agents are discouraged from working alone at an open house.

"We always like for them to have someone accompany them at an open house," she said. "You can't be a sitting duck."

Open houses have always been problematic for agents. Along with the prospect of an assault, there is the potential for theft.

"We've had some situations where medications were stolen, and we always caution homeowners to put things away," Ms. Wesson said. "A lot of sellers don't want their homes held open for this very reason."

Real estate agent Harriet Shaw often sits in her car at a house tour, which gives her the chance to scope out a customer before unlocking the front door.

Ms. Shaw said open houses can be a "setup to get hurt," but many agents are willing to take the risk to sell a property.

"You have to have your radar on," she warned. "I've refused to show properties if the person doesn't seem right."

Ms. Malone, who was attacked almost 10 years ago, didn't have an inkling of the danger she faced when she met a client at her office to shop for houses. Earlier she had shown several homes to the man from Euless.

But while touring a house in Coppell, he suddenly attacked Ms. Malone, stabbing and beating her. He left her bleeding on the floor, stole jewelry and fled in her Mercedes-Benz.

Police later captured Carl Joseph Raspante in Missouri. He pleaded guilty to attempted capital murder and got 40 years in prison.

Ms. Malone said that even with widespread publicity about such attacks, agents remain vulnerable.

"I read a lot of things people put out about safety, but obviously they have never worked out in the field," she said. "We are all self-employed people, and we can't have someone baby-sit us all the time.

"All you can do is take every precaution you can take."

Still, the industry tries to play it safe. Real estate commissions and local associates regularly offer security training to agents and publish brochures with safety tips.

Some builders have installed electronic safeguards.

"We have a security system in every one of our models, and our agents also have panic buttons," said Robin Rigby, corporate director for Darling Homes. "The people who install our equipment say their phones are ringing off the hook."

Still, Ms. Rigby said it is often necessary for salespeople to work by themselves.

"Everyone is on high alert right now, and we are looking at what additional steps we can take," she said.

Adella Woods, who was holding a tour Wednesday for agents at a northeast Dallas home, said security concerns are a growing issue with the industry.

"It's getting more and more dangerous," Ms. Woods, an agent with Ebby Halliday, said. "If someone walks in off the street, you don't know anything about them."

That's why she discourages clients from holding open houses.

"If a home is priced properly, it doesn't need an open house," she said.

Convincing clients can be tough, though. Sellers' surveys consistently cite open houses as among the most important marketing tools.

It's been that way for decades.

"Our industry is focused on doing the same old thing the same old way," Ms. Shaw said. "But no one wants to get hurt.

"When something happens like this, it's an opportunity for all of us to be reminded of the dangers."