When the crash happened, police couldn't work out why.
A car driven by 34-year-old Kari Jo Milberg from Centuria, Wisc., allegedly plowed into a truck heading in the opposite direction. Her 11-year-old daughter and two 5-year-old nieces, who were in the car with her, were killed.
Milberg was seriously injured but survived, as did her 3-year-old son. Milberg said she couldn't remember what had happened.
The accident happened in December 2013. However, as CBS Minnesota reports, police went back to the crash scene in April last year. By then, the snow had melted. They found a phone, which turned out to be Milberg's.
What they discovered, they say, is that Milberg was sending Facebook chat messages to a man a mere two minutes before the crash was reported.
This has led the local district attorney to issue three charges of homicide against Milberg. She faces a maximum of 10 years in jail and a $25,000 fine for each homicide.
The crash investigators' report specifically cited the Facebook chat messages and the subsequent alleged driver inattention as the causes of the accident. The report did add that she had a therapeutic amount of Oxycodone and Midazolam (a sedative) in her system and that her car's tires had poor tread levels.
The Duluth News Tribune reports that Milberg had allegedly also been texting near the time of the crash.
This isn't the first time a driver has been accused of being on Facebook before a deadly crash. Last year, a 20-year-old from North Dakotawhile checking pictures on Facebook. Her SUV allegedly went into the back of another SUV. A passenger in the SUV hit, 89-year-old Phyllis Gordon, died from her injuries.
Whether it happens to be Facebook, texting or any other mobile use, many states have now outlawed using a cell phone while driving. There seems little evidence that this has curbed people's obsessions with their devices, even when it's patently dangerous.
If the police's allegations are true, what must a mother feel if she has caused the death of her own daughter and two other children because she was chatting on Facebook?
The Duluth News Tribune says that the police report offered this opinion: "Milberg should have been aware that her operation of a vehicle while texting/chatting on Facebook Messenger created the unreasonable and substantial risk of death or great bodily harm by texting/chatting while driving."