Nick Reiner‘s attorney Alan Jackson is getting a close look at the crime scene where Nick’s parents — Rob and Michele — were stabbed to death … he’s just been spotted visiting the home where the couple’s bodies were found by their daughter Sunday.

Jackson was fresh from the courthouse, where Nick WASN’T seen today, because he didn’t have medical clearance to appear in court.

Watch the video … you can see Jackson march down the usually quiet road flanked by news crews, causing a commotion with his arrival. Jackson carries a file with him, which he uses to gesture to his team, possibly instructing them on their first moves.

As you know … Alan is one of the most well-known criminal defense attorneys out there, and he’s no stranger to high-profile cases like this one … he recently got Karen Read acquitted of murder in Massachusetts.

In a press conference Tuesday, Los Angeles County District Attorney Nathan J. Hochman came out swinging, saying the death penalty is on the table if Nick is convicted of murdering his parents.

As we reported … Nick was arrested on suspicion of killing his parents after they were found stabbed to death in their Brentwood, California home Sunday afternoon.

TMZ broke the story … Nick got into a heated argument with Rob at Conan O’Brien‘s Christmas party Saturday night, loud enough for others to overhear. Rob and Michele left the party after the fight.

Hours after the party, on Sunday afternoon, Rob and Michele’s daughter Romy discovered their stabbed and bloodied bodies at their Brentwood house. Rigor mortis had already set in, meaning they had been dead for hours.

Romy is the one who called the police and told them her brother Nick — who’d been living at the house — was “dangerous” and should be considered a suspect.

Despite living there, Nick wasn’t at home when Romy made the discovery. Instead, he had checked into The Pierside Hotel in Santa Monica around 4 AM Sunday, using his credit card.

The reservation was made for just a day, but Nick never formally checked out.

When the staff came into his room later Sunday morning, they found the shower “full of blood” and blood on the bed.

“TMZ After Dark” has been tearing up the nightlife for a minute now … so naturally, the next step was bigger, bolder, raunchier — it’s our first-ever gay party on wheels!

We’ve honestly never seen a party like it — history went down Saturday night as celeb hosts Queer Ultimatum’s Vanessa Papa and comedian Izzy Rocha turned all the way up, raging with Ashlee Belzo‘s queer-owned production crew Girls, Gays and Theys.

The bar crawl kicked off at Jumbo’s Clown Room, bounced to Rainbow Bar & Grill, rolled through Beaches Tropicana … and wrapped at Roosterfish West Hollywood for the company’s massive third anniversary blowout.

If that wasn’t enough — surprise! West Hollywood Mayor Chelsea Lee Byers popped up, and we took her to Jumbo’s for the first time. Cameras weren’t allowed inside, so yeah … let your imagination do the heavy lifting …

The party spilled outside — we kidnapped one of Jumbo’s dancers, Caroline Blaike, cuffed her, and brought her aboard, where she delivered a lap dance to the mayor so steamy it literally fogged up her glasses🙈 … with the best DJs in town, Toxic Kitty and Liz Wentling, spinning.

So yeah, if you’re looking for the wildest party in town, hit up TMZ After Dark 🎶’cause you’re on the right track, baby… if you were born this gay! 🎶

1:15 PM PT — Los Angeles County District Attorney Nathan J. Hochman came out swinging in his latest comments on the Rob and Michele Reiner double-murder case … he says the death penalty is on the table if their son, Nick Reiner, is convicted of murdering his parents.

Hochman says Nicks is going to be charged with two counts of first-degree murder, and he says the charges come with stiff penalties, if convicted … a maximum sentence of life in prison without the possibility of parole, or even the death penalty.

The D.A. was quick to say there’s been no final decision on going after the death penalty here, but the fact he even mentioned it right off the bat is pretty interesting.

Los Angeles County District Attorney Nathan J. Hochman and LAPD Chief Jim McDonnell are set to hold a press conference at 1 PM PT to update the public on the Rob and Michele Reiner double-murder case.

As we reported … Rob and Michele’s 32-year-old son Nick was arrested on suspicion of killing his parents after they were found stabbed to death in their Brentwood, California home Sunday afternoon.

Nick’s first court appearance in connection with the murders was scheduled for today, but was taken off the books after he was not medically cleared to appear in court. His attorney told TMZ this morning he has not received any filing yet from prosecutors.

While Nick lived at home with his parents, Romy noted to the police Nick wasn’t at the home when she arrived, insinuating he fled.

We now know Nick checked into The Pierside Santa Monica hotel around 4 AM Sunday, using his credit card. The reservation was made for just a day, but Nick never formally checked out. When the staff came into his room later Sunday morning, they found the shower “full of blood” and blood on the bed.