How did Demeter findout what happened to her daughter?

Demeter discovered what happened to her daughter, Persephone, when she learned from Hecate, the goddess of magic and witchcraft, that Persephone had been taken by Hades to the Underworld. Hecate guided Demeter to HeliOS, the sun god, who revealed the truth about Persephone's abduction. Heartbroken and enraged, Demeter searched for her daughter, leading her to neglect the earth and cause a great famine until she was reunited with Persephone.