Reiner was arrested on Dec. 13 in connection to the deaths of his parents, Rob Reiner and Michele Singer Reiner, and was charged with two counts of first-degree murder on Tuesday. Now, a police source has provided more information about his experience at the Twin Towers Correctional Facility in Los Angeles.

Rob Reiner's son Jake and daughter Romy are being surrounded by support after their parents were killed and brother Nick was charged with murder. "This nightmare came out of nowhere for them," a source tells PEOPLE.

Rob and Michele Reiner's final hours were spent with their son, Nick, who now is accused of killing them. Inside the final, chilling hours.

The Fox News Entertainment Newsletter brings you the latest Hollywood headlines, celebrity interviews and stories from Los Angeles and beyond.

Other projects that have Reiner’s name attached, according to IMDb, are the movies “Airtight,” “El Fuego Caliente,” “Travel Writing” and “Whiskey River,” as well as a reboot of the 1970s British TV series “Fawlty Towers.” They all appear to be in early stages of development.

New details emerge about Rob Reiner’s final evening as a restaurant owner recalls a normal night that turned tragic days later.

The shocking double murder of Rob Reiner and Michele Singer Reiner has deeply affected other parents whose kids struggle with substance abuse. Addiction expert Heather Hugelmeyer chats with PEOPLE to provide advice for families navigating the 'grief' and 'guilt' of addiction.