On Dec. 16, in Madison, Wisconsin, 15-year-old Natalie Rupnow shot and killed two other people before taking her own life.

The work could take weeks, police said. Authorities are also mulling criminal charges, although it's not clear against whom.

A California man apologized for his connection to the 15-year-old shooter who killed a student and teacher in a Madison ...

A California man apologized for his connection with the Madison school shooter. SAN DIEGO - A California man apologized ...

A California man apologized Friday for his connection to a 15-year-old girl who fatally shot a teacher and a fellow student ...

Alexander Paffendorf was detained late last month after FBI agents said he was plotting a mass shooting with Natalie "Samantha" Rupnow.

A Carlsbad man who authorities say communicated with a Wisconsin school shooter appeared in a San Diego courtroom on Friday.