A 19-year-old Savage man was charged with second-degree murder Tuesday for allegedly killing a woman who answered an online job posting for a baby-sitting job.

Michael John Anderson allegedly shot Katherine Ann Olson in the back and killed her, according to a criminal complaint filed in Scott County District Court. His bail was set Tuesday at $1 million.

Authorities said blood stains and drag marks were found in Anderson's home, and a .357-caliber Magnum was found in his bedroom. A neighbor saw Olson's gold Hyundai Elantra sitting in front of Anderson's house for over two hours on Thursday, the complaint said.

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Olson had gone to Anderson's home to inquire about a baby-sitting job she had seen advertised on the popular Internet bulletin board, Craigslist. She believed she was answering an ad from a married couple who had just relocated to the Twin Cities.

Olson, 24, left her apartment in south Minneapolis on Thursday morning and never returned. Her body was found Friday night in the trunk of her car, which had been abandoned in a Burnsville park about five blocks from Anderson's home. Olson's purse and a bag containing bloody towels, one of which had Anderson's name on it, were found in the garbage nearby.

Anderson initially told police he had nothing to do with the murder, and he denied having phone contact with Olson. But cell phone records indicated he talked with her Thursday morning. Anderson also said he had not used Craig's List since January, but the e-mail address in the ad matched Anderson's. Anderson told police his mother and three friends had access to the account.

When confronted with evidence, Anderson then admitted he was there during Olson's murder, but that she was killed by a friend of his who "thought it would be funny," according to the complaint.

Olson was a 2002 graduate of Park-Cottage Grove High School, where she was co-valedictorian. She graduated from St. Olaf College in 2006.

Olson had taken nanny jobs at least twice before, including a job in Turkey, after answering online ads. Her family posted a letter on Facebook, saying that Olson had used Craigslist in the past to find "kindred spirits and opportunities." The family letter also said Olson loved children, and was involved in the church choir, a women's group and numerous outreach activities.