Della Sorenson kills the first of her seven victims in rural Nebraska by poisoning her sister-in-law's infant daughter, Viola Cooper. Over the next seven years, friends, relatives, and acquaintances of Sorenson repeatedly died under mysterious circumstances before anyone finally realized that it had to be more than a coincidence.
Two years after little Viola met her demise, Wilhelmina Weldam, Sorenson's mother-in-law, was poisoned. Sorenson then went after her own family, killing her daughter, Minnie, and husband, Joe, over a two-week period in September.
Waiting only four months before marrying again, Sorenson then settled in Dannebrog, Neb. In August 1922, her former sister-in-law came to visit with another infant, four-month-old Clifford. Just as she had done with Viola, Sorenson poisoned the poor child with a piece of candy. The unfortunate Mrs. Cooper, still oblivious to what was happening, came back again in October to visit with yet another child. This time, Sorenson's poison didn't work.
Early in 1923, Sorenson killed her own daughter, Delia, on her first birthday. When Sorenson's friend brought her infant daughter for a visit only a week later, the tiny infant was also poisoned. After an attempt on Sorenson's second husband's life left him sick--but not dead--authorities began to think that there might be a connection between these series of deaths.
Finally, in 1925, Sorenson was arrested when she made an unsuccessful attempt at killing two children in the neighborhood with poisoned cookies. She confessed to the crimes, saying, "I like to attend funerals. I'm happy when someone is dying." Sentiments like this convinced doctors that Sorenson was schizophrenic, and she was committed to the state mental asylum.
Taken from: http://www.history.com/this-day-in-history/a-string-of-mysterious-deaths-surrounds-a-nebraska-woman [23.07.2013]