Nick Reiner was disciplined in jail after he allegedly became “extremely hostile” toward deputies while waiting to be escorted back to his cell following a shower.

“He was recalcitrant, extremely hostile, creating a verbal disturbance, refusing to follow rules and not listening to any commands,” a source told People Wednesday.

“He was yelling, screaming, being disrespectful and shouting many profanities.”

According to the insider, Reiner had finished showering and changed into a fresh set of county-issued inmate clothing.

However, he became increasingly frustrated that deputies had not immediately returned to escort him back to his cell, but instead were responding to an apparent overdose that occurred in another unit.

“[He] became very impatient. He was upset and hostile because no one was coming back right away and he wasn’t attended to,” the source added.

“He had finished showering and changed and wanted to return to his cell. When it took too long, he became frustrated and angry.”

Nick — who is accused of murdering his parents, Rob Reiner and Michele Singer Reiner — was allegedly screaming, using profane language and directing hostile remarks at both a sheriff and a sergeant, according to the source.

The deputy allegedly called for backup, prompting approximately three additional guards to respond. Despite Nick’s erratic behavior, the source noted that the confrontation never became physical.

Nick was issued a disciplinary write-up for allegedly violating jail rules, the source said. He also lost several inmate privileges for five days, including phone calls, visitation and commissary access.

A deputy supervisor issued the disciplinary report, which was later reviewed by a supervising officer. A disciplinary officer then met with Nick in his cell to explain the violation, discuss his behavior and notify him of the temporary sanctions.

The alleged incident unfolded at 8:15 a.m. on April 27 inside Tower 1 at the Los Angeles County Twin Towers Correctional Facility.

The 32-year-old is currently housed alone in a specialized medical observation jail unit under heightened security measures.

Last month, a source close to the Reiner family revealed that Nick is “rapidly deteriorating” behind bars.

“He is rapidly deteriorating. No one would recognize him. He is almost bald because they have to keep his hair super short to keep the bugs out, and he is super skinny because of the intense medication he is on. His eyes are very sunken in,” the insider told the Daily Mail.

“Nick has not been well for many years, but before jail some of his personality could be recognized. Not now. He is like a babbling child, totally out of it,” the source continued. “It’s so bad his lawyers have a hard time talking to him.”

Nick was arrested by Los Angeles Police Department officers on Dec. 14, 2025, shortly after his dad and mom — who were 78 and 70, respectively — were found stabbed to death inside their Brentwood home.

He was charged with two counts of first-degree murder with special circumstances of multiple murders and personal use of a knife.

If convicted, Nick faces a possible death sentence or life in prison without the possibility of parole.