SAVAGE, Minn. —  Police in Minnesota say an online ad may have cost a young woman her life.

They say Katherine Olson was last seen by friends when she went to meet someone about a nanny job posted on Craigslist.org, the Internet bulletin board.

A day later, her body was found in her car at a Minnesota nature preserve. Police declined to say how the 24-year-old was killed.

Authorities say a 19-year-old man who they believe placed the ad is being held pending charges. Authorities did not release his name but said charges could be filed as soon as today.

Olson graduated from St. Olaf College last year. Her family said she had taken nanny jobs at least twice before after answering online ads