Sajid and his son, Naveed, 24, are suspected of having carried out the attack during a Hanukkah celebration on Sunday, killing 15 people and leaving dozens of others injured.
Their daughter Romy, 27, who lives across the street, then went to check on them herself and called emergency services after discovering a horrifying scene inside the home.
Nick, who has cycled in and out of rehab over the years, said he got the idea to contact a sex worker online from another patient he met while attending outpatient treatment.
The brutal killings and Nick's subsequent arrest have sent shockwaves through Hollywood, leaving the Reiners' many friends in the industry stunned and grieving.
Due to his personal struggles, Nick reportedly had a strained and complicated relationship with his father in the years before the famed director's death.
Dispatch audio reveals that Moore's wife had called 911 ahead of his arrest on Wednesday, expressing concern about his mental state as the assault allegations unfolded.
Just hours earlier, Moore had been fired as Michigan's head coach due to an inappropriate relationship with a staff member, whose identity has not been revealed.