Two Massachusetts sisters will be buried with the brother who killed them with a kitchen knife.

Seventeen-year-old Samantha Revelus and her five-year-old sister, Bianca, were killed at their Milton home Saturday.

Police burst into their apartment and say they saw the girls' brother, 23-year-old Kerby Revelus, decapitating Bianca. Police say they shot Kerby Revelus dead as he tried to attack another sister, nine-year-old Saraphina.

A spokesman for the children's parents said Monday that they are making arrangements to bury their three children together. He said they are "in shock and disbelief," and have no explanation on why their son would kill his sisters.

Saraphina had surgery Monday and is expected to survive.