Brian Williams appeared calm during his first court appearance Wednesday.
The 24-year-old Rancho Penasquitos man faces two murder charges for the stabbing deaths of his mother and sister.
His mother, Donna Williams, was a decorated veteran of the San Diego Police Department. His sister, Bree Williams was a standout athlete and recent graduate of Mt. Carmel High School.
During Williams' arraignment, new details were released about the double homicide that took place around 1:30 a.m. Monday at the Williams' home on Paseo Montril.
Witnesses who heard screams coming from inside the home called 911. When officers arrived, they found Bree Williams' body on the front walk way. Her brother was calmly sitting next to her, a large kitchen knife not far away.
Donna Wiliams was found inside the home.
Prosecutors said both victims were found with their throats slit.
Witnesses told investigators that after Williams watched his sister fall off the second-story balcony outside her bedroom, Brian Williams calmly walked back through the upstairs bedroom window, walked to his sister's body and sat down next to her.
Williams' public defender asked for his client to be put in protective custody because, he says, he wants deputies to observe Williams in order to determine for themselves that he suffers from mental illness.
Williams will continue to be held without bail and will be back in court next week.