Soon after their arrival, violence erupted in eastern Pennsylvania's Susquehanna River valley. Although the Slocum family remained in the settlement, many others fled during the Battle of Wyoming in July 1778, when British forces and Seneca warriors destroyed Forty Fort near Wilkes-Barre, killing more than three hundred American settlers. The Slocum family survived the battle, and felt their Quaker beliefs and friendly relations with the natives would protect them. However, on November 2, 1778, while Jonathan was away, three Delaware warriors attacked the Slocum family farm near Wilkes-Barre. Ruth and all but two of her children escaped into the nearby woods, but the Delaware captured five-year-old Frances, her disabled brother, Ebenezer, and Wareham Kingsley, a young boy whose family was living with the Slocums. Ebenezer was released at the farm, but Frances and the Kingsley boy were taken captive. Slocum never saw her parents again. Natives killed her father and grandfather on December 16, 1778. Slocum's mother, who died on May 6, 1807, never gave up hope that her daughter would be found.