CLINTON, Md. (CBSNewYork/AP) – Three girls under the age of 10 were stabbed to death in Maryland, including two sisters from New Jersey.

Police said 24-year-old Antonio Williams confessed to killing his sister 6-year-old Nadira Withers and relatives Ariana, 9, and Ajayah, 6, Decree, of Newark.

Withers’ mother discovered their bodies when she returned home from work Friday morning in Clinton, a suburb of Washington, D.C.

Williams has been charged with first and second degree murder. Police are working to establish a motive.

(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)