Updated

A suburban Chicago woman is charged with murder in the death of her 6-month-old granddaughter.

Authorities said Monday that 61-year-old Alfreda Giedrojc of Oak Lawn used a sledgehammer and knife to kill baby Vivian Summers on Sunday morning. Prosecutors say the grandmother placed the baby on the floor and hit the baby repeatedly with the sledgehammer. They say the woman then retrieved a kitchen knife and slit the baby's throat.

Giedrojc is charged with first-degree murder and held without bond in the Cook County jail. A message left at a phone listing for Giedrojc in Oak Lawn was not immediately returned.

Oak Lawn Police Chief Michael Murray called the baby's death "a tragedy."