Nick Reiner, son of Rob Reiner and Michele Singer Reiner, has been put on suicide watch after his arrest. He is suspected of murdering his father and mother, and is in jail without bail. According to sources from TMZ, who received information from law enforcement, Nick is currently placed in an administrative segregation at Twin Towers Correctional Facility in Los Angeles.The New York Post reported that Nick had spent some time in rehabilitation and had been in and out. Insider sources close to the Reiner family have also revealed that Michele Reiner had been worried about her son and his mental illness, as well as alleged substance use. She had expressed her concerns to her friends. According to Nick's mother, she said:"We've tried everything."The Los Angeles Police Department revealed that Nick was arrested on Monday, after they found Rob Reiner and his wife, Michele, in their Brentwood home, with their throats slit.What happened between Nick Reiner and his parents before their murder?According to sources from TMZ, Nick Reiner and his parents attended Conan O'Brien's Christmas party on Saturday night. However, not everything was holly and jolly with the Reiners. The sources revealed to TMZ that Nick Reiner was arguing with his parents loudly at the party. Other people who attended could probably have heard the exchange of words.After the shouting match, Rob and Michele Reiner decided to leave the Christmas party to go home. It was unclear if Nick went back with his parents or not that night. However, another source shared that while Nick was at the party, he looked out of place and did not really attempt to make conversation with the other guests.Nick had always been open with the public about his mental health struggles and drug addiction. He even wrote the film, Being Charlie (2015), which his father directed, and won a SAMHSA (Substance Abuse and Mental Health Services Administration) Voice Award.Nick Reiner has been arrested for allegedly killing his parents and is on suicide watch in jail. He had long struggled with mental health issues and drug addiction, which worried his mother. However, he had been open about his struggles with the public, even writing the 2015 film, Being Charlie, which was loosely based on his life. It has also been reported that he argued with his parents shortly before the tragic incident.Also read: Who is Rob Reiner’s son Nick Reiner?