"People spend more time determining which refrigerator they're going to buy than who they're going to allow into their home or even into their bedroom," said Joe Navarro, a retired FBI agent who consults and speaks on nonverbal behavior.
Most people assume nothing will go wrong during a visit from a representative of a well-known company. Navarro's advice: Pay attention. If a contractor arrives with his uniform askew, if he smells of alcohol, trust your instinct and turn him away.
"The subconscious part of our brain reacts to people," said Navarro, who teaches criminal justice at St. Leo University in Florida. "If there's something not quite right, don't let that person into the house."
He tells people to have a friend or family member present with them when work is being done. If that's impossible, have them check in by phone. Always, keep distance between yourself and the workman.
But people can take precautions and still be victimized, he noted. And that's scary.
Homeowners ask: What are they supposed to do, run criminal-background checks? Besides, there's no guarantee someone who has been peaceful won't become violent.
"I'm usually the one who is home alone," said Melissa Warner, 31, a Hahnemann University Hospital nurse who shares a Fishtown rowhouse with her husband.
She works three 12-hour shifts a week and is often off during daylight hours that seem perfect for deliveries or contractors. She recently had a cable-company worker in her house, while she was there alone, for three hours.
"I didn't feel uncomfortable. But it crossed my mind, this is a really long time to have a stranger in your house," said Warner, pregnant with her first child. "It's definitely made me think, as far as having contractors who I don't know, or who aren't friends of friends, that I should arrange it when a friend could be here or when my husband is home."
Police have charged Jason Smith, a 36-year-old Levittown exterminator, in the death of Ketunuti. They say some type of altercation occurred after he arrived at Ketunuti's Graduate Hospital-area home Monday.
Smith told police he had been booked for the call through Dave Bilyk Exterminators, a Newtown company for which he was a subcontractor.
Better Business Bureau records show no complaints against the firm. Reviews on Angie's List, a website where people post detailed opinions of plumbers, dentists, cleaners, and others, give Bilyk Exterminators an overall "A" rating. Two reviews mention a technician named "Jason" who was described as professional, courteous, and efficient.
Efforts to reach Bilyk Exterminators for comment were unsuccessful.
"In our homes we feel very safe - this is our territory," said Elizabeth Dowdell, a professor at the Villanova University College of Nursing who studies victimology. "But people need to know it's OK to leave it."
That is, she said, if a situation feels wrong, get out. And be sure you've left an exit route.
After Ketunuti's killing, the National Pest Management Association, a trade group, reiterated advice to help property owners stay safe:
Ask friends and neighbors to recommend companies they have used.
Ask the firm whether it conducts employee background checks.
If you feel uncomfortable being home alone with a worker, invite a friend to visit.
"It's a subject that now is hitting us in the face," said Howard Silver, a general contractor in Glenside.
He tells clients up front: The worker coming to your house is my employee, not a subcontractor, and he's worked for me for at least five years. He's trustworthy.
Andrews, the Spring Garden marketer, lived in other big cities before coming to Philadelphia, so she's conscious of urban-safety issues.
Her husband, Erwin, served in the Air Force and tends to be security-minded.
They're even more aware of visitors since the arrival of their daughter, 10-month-old Sanaa.
Andrews estimates contractors come to their home six to 12 times a year.
Sometimes, particularly if two or three workers show up, she'll step outside to wait.
The doctor's killing struck her forcefully.
"It hits you because it happened at home, a well-to-do professional person in a nice neighborhood," she said. "It made me feel like I need to be even more vigilant."
Contact Jeff Gammage at 215-854-2415, firstname.lastname@example.org, or follow on Twitter @JeffGammage.