Police were alerted to a report of an assault on Perry Street about 2:15 a.m. Saturday.
A fourth woman was also attacked, but managed to escape the home and call for help.
'When he came here last night, the doors were secured and he became enraged, ' said Lt Fitzpatrick. "With this framing hammer, he broke through the basement door". Meanwhile, Bobby killed her sister's other friend Janel, who he found in a room upstairs, in the same manner.
The women suffered blunt force trauma, but cops would not elaborate, said Det.
'He went to the garage, he obtained a large hammer.With this hammer, he broke through the basement door'.
Police said Vanderhall then found his mother in the living room and started to bludgeon her with the hammer.
The Post reported that her wrist was broken fending off the attack.
Fitzpatrick said Vanderhall had a history of "emotional issues" and had on two occasions been taken from his mother's home to a medical centre.
Next, he found his sister, 29-year-old Melissa Vanderhall, and one of Melissa's friends on the staircase and beat them with the hammer, authorities said.
According to police, Lynn Vanderhall had an order of protection against her mentally troubled son. "Beautiful, outstanding people, that's what I want the world to know", said a family relative, Juanita Johnson.
The police described Bobby as more than six feet tall and at weighing least 230 pounds.
Vanderhall was awaiting arraignment on three murder charges and an attempted murder charge.