A New Jersey murder trial has been thrown into chaos thanks to a juror who posted “Sitting on the jury LMAO” on Facebook — prompting a judge to boot her off the case.

The lawyer for suspect Liam McAtasney — who is charged with fatally strangling friend Sarah Stern and dumping her body to steal her inheritance — is now demanding a mistrial, claiming a fair trial is now impossible, NJ.com reported on Wednesday.

The offending juror’s comment was in response to a news article about Stern’s 2016 death.

A tipster alerted Monmouth County Superior Court Judge Richard English to the post — and he hauled the juror in for questioning last Thursday.

She told the jurist that her 15-year-old sister made the comment, which has since been deleted — but he dismissed her anyway.

When the trial resumed on Wednesday, five other jurors told English that they’d heard their dismissed peer had posted on Facebook but didn’t know exactly what it said.

One said they reached out to her on Facebook and learned that she’d been excused over the comment, according to the Asbury Park Press.

The trial, which began in late January, is only held on Tuesdays, Wednesdays and Thursdays.

Prosecutors were expecting to call their final witnesses on Wednesday.

But McAtasney’s attorney Carlos Diaz-Cabo asked English for an adjournment so he could file a motion for a mistrial. English granted the request — visibly angering prosecutors Meghan Doyle and Christopher Decker.

McAtasney is accused of throttling Stern, 19, to death in her Neptune City home before stealing roughly $10,000 in cash that was left in a shoebox by her late mother. He and co-defendant Preston Taylor allegedly tossed Stern’s body off the Route 35 bridge in Belmar. Her body has never been recovered.

Taylor testified that McAtasney, his former roommate, enlisted his help thinking Stern’s inheritance was actually $100,000.

“It’s the type of money that somebody would kill for,” McAtasney allegedly told Taylor, 21.

Taylor pleaded guilty in 2017 to a slew of charges and agreed to testify against his ex-pal. He faces between 10 and 20 years.

English said he would decide on Thursday whether to declare a mistrial.