Brooklyn mass shooting suspect Frank James once posted a chilling video from another packed Big Apple subway train — slowly pointing his finger at passengers as if picking out targets.

The troubled 62-year-old — who was arrested Wednesday after a massive manhunt — posted the eerie, 47-second clip in July 2020 to his social media, which was full of violent threats and support for black power leaders.

They included rants about Mayor Eric Adams — forcing Hizzoner to get beefed-up protection — while also gloating about heroic NYPD cops shot dead on duty.

The subway clip shows a finger just in front of the camera as it slowly scans the crowded subway car, slowly pointing toward oblivious straphangers.

As he does so, his voice slowly mumbles, similar to how witnesses say the shooter did after he set off a smoke bomb and shot 10 people, also injuring 19 others, on the Manhattan-bound N train during rush hour Tuesday.

“This is actually freaking me out,” one recent viewer wrote, while another called it “creepy AF.”

The clip, called “The good ole days,” was recorded in August 2020, James explained in the comments.

However, James’ regular social media posts appear to show him fantasizing about killing people for years.

In one 2019 post, he shared a meme saying, “I like you … I think I will kill you last.”

One of his last Facebook posts before Tuesday’s carnage was a photo of a man pointing a gun straight at the camera, which he shared Friday.

Another post this month showed the bloodied, gun-carrying hand of the assassin from the video game Hitman Absolution, about a killer hunted by cops for “pursuing redemption in a corrupt and twisted world.”

James — who says he is a native New Yorker in his videos — also celebrated actual violence, posting a photo of heroic NYPD cops Jason Rivera, 22, and Wilbert Mora, 27, who were shot dead during a Jan. 21 domestic call in Harlem.

“NYPD under attack dam shame,” he wrote.

The cops’ deaths — which led to an unprecedented turnout for their funerals — was also a topic for many of James’ lengthy rants on YouTube in which he claimed to be a “Prophet of Truth.”

In one, he sympathized with the cops’ shooter,  career criminal Lashawn McNeil, suggesting he was only carrying out the purpose that a racist society had pushed him into.

“What can you expect?” he titled a Feb. 1 rant, blaming the “stereotypes” that “whit motherf–kers” have of all black men.

“Nothing else is encouraged, except violence,” he insisted. “I’m expected to be violent, I’m expected to be a criminal, and when I’m not there’s something wrong with me,” he claimed.

“That’s enough to make you want to hurt somebody,” he warned ominously.

Other posts showed him celebrating black power leaders like Angela Davis and Malcolm X, with James more than 30 years ago wearing a T-shirt of the soon-to-be-slain black nationalist leader holding a weapon.

He also shared an image of controversial late Nation of Islam leader Elijah Muhammad, using his preferred title as “The Messenger of Allah.”

Other photos showed he was angry about rising gas prices — posting a photo of someone paying $50 — while also expressing homophobia.

“Love your neighbor,” one meme he shared said, before adding, “He’s gay, never mind.”

James rarely posted anything upbeat, save in 2013 when he shared news that he had won $5,000 in a New Jersey Lottery.

Instead, he mostly made clear he had death and violence in mind for years.

In August 2020, he posted a disturbing photo of a blue body bag on a gurney, saying it was the rightful place “FOR EVERYBODY THAT WANTS TO PUT ME IN MY PLACE.”

A day later, he posted a photo of dozens of bullets with the caption, “Nothing says FU better than some of these FU.”

He recently also posted a photo of teen Kenosha gunman Kyle Rittenhouse, writing, “And a child should lead them.”

Like many of his posts, that led to a flurry of comments after Tuesday’s outrage, with one writing of Rittenhouse, “Too bad Kyle wasn’t on that train to blast your ass.”

Many of his disturbing messages hinted at his personal thoughts of gun violence.

“You may not be able to beat ’em but you can sure as hell shoot ’em,” said a meme he re-shared in October 2020, four years after first posting it.

“Of all things remember this … every motherf–ker respects a gunshot wound,” another meme shared the same month said.

In March he reposted a meme he first shared five years earlier, saying, “They say the pen is mightier than the sword, I say the bullet is mightier than both them.”

“Please don’t make me prove it,” James warned.

James’ Facebook page was finally taken down just after 1 p.m., with a spokesperson for the platform’s parent company Meta confirming to The Post that it was “removed in line with our policies.”

His YouTube channel went down about an hour earlier, with a message saying, “This account has been terminated for violating YouTube’s Community Guidelines.”

Such action is nothing new for James, who revealed in a video last month that at least four of his channels under various “Profit of Doom” monikers had been removed because “YouTube has found a way to deal with people like me.”