In the days leading up to his arrest for the alleged murder of his parents, Nick Reiner, son of renowned filmmaker Rob Reiner, exhibited concerning behaviors that were described as “abnormal” and “drained.”

According to an employee at a Sinclair Gas station in Brentwood, California, Nick was last seen there around two weeks prior to the incident. The worker noted that Nick, who typically engaged in friendly interactions, appeared unusually fatigued and distant during this visit.

Despite his changed demeanor, Nick did not seem to be under the influence of drugs or alcohol when he stopped by the gas station to purchase a pack of cigarettes, the employee reported.

The gas station staff noted that the Reiner family were regular patrons, with one of them mentioning a 15-year acquaintance with Nick.

As earlier reported by Page Six, Rob Reiner, aged 78, and his wife, Michele Singer Reiner, 70, were tragically found deceased in their Brentwood residence on Sunday.

Nick was arrested and charged with two counts of first-degree murder. He is currently being held without bail at the Twin Towers Correctional Facility in LA.

The Post obtained surveillance video of Nick calmly walking past the Sinclair Gas station, which was blocks away from his parents’ home, just hours before Rob and Michele were killed.

The “Being Charlie” writer had a history of violent outbursts and drug addiction.

The night before the killings, a source confirmed to The Post that Nick “freaked out” and had a massive blow-up with his parents at Conan O’Brien’s Christmas party.

On Wednesday, the Los Angeles County Medical Examiner released the couple’s official cause of death. The filmmaker and the actress died from “multiple sharp force injuries” and their passing was listed as a homicide.

That same day, Rob and Michele’s kids, Romy, 28, and Jake, 34, released a statement about the “horrific” murder of their parents.

“Words cannot even begin to describe the unimaginable pain we are experiencing every moment of the day,” they told Page Six.

“The horrific and devastating loss of our parents, Rob and Michele Reiner, is something that no one should ever experience,” the siblings added.

“They weren’t just our parents; they were our best friends. We are grateful for the outpouring of condolences, kindness, and support we have received not only from family and friends but people from all walks of life.”

Romy and Jake concluded their statement by asking for “respect and privacy” as they navigate this difficult time. They did not mention their brother, Nick.