Hattie Livermore Whitten was born on July 24, 1862, in Dover, Maine. She was one of two daughters in her family, born to David and Esther Livermore. Not much is known about her early life in Dover. However, it has been reported that her family was considered respectable.

At some point in her life, Hattie married a man named Harry E. Whitten. Together, they had three children: Fannie, Jennie, and Lewis.

In 1900, Hattie Livermore Whitten's husband, Harry, died suddenly. His death raised suspicion, as many believed it was due to poisoning by Hattie. After his death, her behavior changed, and people noticed she seemed to be addicted to morphine.

The Whittens moved to Dexter, Maine, in September 1902. Hattie soon began running a boarding house. On September 19, her 11-year-old daughter, Fannie, died unexpectedly. The coroner attributed her death to meningitis. However, this diagnosis was viewed with suspicion because Fannie had seemed well before her death. Hattie had insured Fannie and received $85 from the insurance policy.

About a month later, Hattie's other daughter, 9-year-old Jennie, died suddenly on November 27, supposedly from heart failure. Jennie was also insured by Hattie, for $50. Authorities became suspicious. They called for an examination of Jennie's body, where the coroner found arsenic and strychnine. An arrest warrant for Hattie was issued for Jennie's murder.

Hattie was arrested on November 29, right after returning from Jennie's funeral. While she was in custody, officials exhumed Fannie’s body for further testing. It is believed that poison was also found in Fannie’s remains. Hattie pleaded not guilty to the charges against her.

On November 30, while being held under house arrest, Hattie hanged herself using two towels tied together. She was discovered shortly after the deputy had left the house. Medical staff attempted to revive her but were unsuccessful. Hattie was buried alongside her daughters.

Later investigations revealed some unusual facts about her actions. Before Fannie died, Hattie was seen buying laudanum, arsenic, and castor oil. Similarly, she purchased arsenic and strychnine shortly before Jennie's death. There were also suspicions about her intent as she had been seen trying to capture the attention of a man who did not want to marry a woman with children.