Karl Olson said his older sister, Katherine, frequently used craigslist, the popular online network that offers free classified advertising.

“She found two other nanny jobs on craigslist over the years,” he said.

Karl Olson said it wasn’t unusual for his sister to use the site to search for jobs and meet people.

“That’s just Katherine’s personality,” he said. “There are thousands and thousands of people that would’ve done the same thing and are doing the same thing.”

Katherine Olson left her apartment last Thursday to respond to a craigslist listing for a babysitting job she was interested in.

The 24-year-old was later found dead in the trunk of her car, shot in the back.

Authorities detained 19-year old Michael Anderson of Savage in connection with her death.

According to the criminal complaint, he said he was present at her death, but someone else killed her.

Anderson was charged with second-degree murder Tuesday. Bail was set at $1 million. If convicted, he could face up to 40 years in prison.

Karl Olson said his sister, an “adventurous woman,” had gone on dates with people she met through craigslist.

Nothing serious came out of the dates though, he said, adding that her death was not connected with those previous dates.

“That’s what makes this a really peculiar case,” Karl Olson said. “They had no relationship to each other.”

Craigslist is a for-profit business with a site used by more than 30 million people, according to its Web site. Clients post more than 25 million new classified ads and 1.5 million job listings each month.

Sarah Sevcik called Katherine Olson her best friend, adding that the two had been neighbors in Cottage Grove since fourth grade before both attended St. Olaf College.

Katherine Olson never expressed concern with craigslist to Sevcik, she said.

She met “good friends” on the Internet, Sevcik said, and the best friend of Katherine Olson’s older sister had even met her husband through craigslist.

Officer Dale Hanson of the Minneapolis Police Department said he’s only seen a couple incidents linked to online networking sites, mostly involving the sexual exploitation of children.

He said some community response police teams have been looking into prostitution-related online activity.

Sgt. Jesse Garcia, public information officer for the Minneapolis Police Department, said people need to be cautious of online acquaintances.

“You should treat them as a stranger,” he said, “because that’s exactly what they are.”

Garcia said if a person goes to a job interview based on an online post, he or she should consider basic safety precautions, such as telling those plans to friends and family.

Interviews like that should take place in public, not a house, he said.

Karl Olson said general safety recommendations from police are valuable.

“There’s merit to what they’re saying,” he said. “I think there’s something to be said about the need to take a friend and meet in a public place.”

“Unfortunately,” Karl Olson said, “We hear it all too much, which makes us perceive it to be just a standard-protocol response.”

Craigslist has basic safety tips listed on its site.

“With billions of human interactions facilitated through craigslist, the incidence of violent crime has been extremely low,” the site said. “Nevertheless, it’s very important to take the same precautions online as you would offline.”

Garcia said he thought a family looking for a babysitter would appreciate a prospect’s caution and concern if he or she asked to meet in a public place.

“If someone was really looking for a nanny and you asked a question like that,” he said, “they would really respect that.”

Professor Chris Uggen, chairman of the sociology department, said the circumstances surrounding Katherine Olson’s death are rare and similar things could stem from simpler technologies.

“A notecard posted at the Laundromat could’ve yielded that same problematic situation,” he said.

Uggen said technology lends itself to a variety of good and bad uses.

“Anytime there’s a new technology, you’ll often see someone using it to commit crime or further their own ends,” he said. “And craigslist is no exception.”

But he said networking sites do beneficial work the majority of the time.

“The overwhelming probability is that the ads placed there are legitimate,” Uggen said. “You create wonderful opportunities for good things to happen as well as terrible things to happen.”

Karl Olson said he understands the benefits of sites like craigslist, which he called a “regular tool for people of our generation” that has become part of our culture.

“There are millions of good people on craigslist,” he said. “There are many, many positive things that come out of this resource.”

Karl Olson said craigslist is not to blame for what happened to his sister.

“This is not a common occurrence,” he said.

People should not be scared away from the Web site because of what happened to his sister, Karl Olson said.

“People should continue to use it,” he said. “We must recognize that we are the ones with responsibility.”