TAMPA — In a shaky cell phone video, a young man in the driver's seat slams through the gears of his manual transmission as the engine roars and club music plays on the stereo.

A speed registers across the screen — first 82.6 mph, then 115.6 mph. A woman is heard giggling during the 10-second clip, apparently filmed from the passenger seat.

The Florida Highway Patrol believes the video, posted on the social media app SnapChat, shows Pablo Cortes III, 22, in the moments before his Volkwagen Golf crossed a median along E Martin Luther King Jr. Boulevard on Wednesday night and slammed nearly head-on into a Toyota minivan.

Cortes, his passenger and three people in the van — a mother and her two children — were killed. The driver of a third car was seriously injured.

The FHP said the video, first obtained by WFTS-TV-Ch. 28 and shared with troopers, is now part of the crash investigation. It appears to support what troopers said they already knew: Cortes was exceeding the 50 mph speed limit when he apparently lost control minutes after the video was posted at 9:38 p.m.

A preliminary FHP crash report put the time of the crash at 9:47 p.m.

"It shows a driver showing a high disregard for himself and his passenger that claimed the life of a mother and two children," said Sgt. Steve Gaskins.

The video also added fuel to criticism leveled at SnapChat for including a feature that enables users to tap into a phone's global positioning system to post real-time speed information over a photo or video.

Critics said the filter encourages users to speed at the same time they're distracted by their phones.

"It incentivizes somebody to do something they know is not safe, but they do it anyway for the sake of the picture or video," said Katie Bassett, who has written about distracted driving and the SnapChat speed filter for the Safer America consumer safety blog. "It's just instigating the user to get up to a dangerous speed and then post it online."

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That's the premise of at least one lawsuit filed by Atlanta attorney Michael Neff against SnapChat and a driver who was accused of using the filter at the time she crashed into another car.

The plaintiff, Maynard Wentworth, was merging onto a four-lane highway outside Atlanta in September 2015 when his Mitsubishi car was struck by a Mercedes sedan "so violently it shot across the left lane into the left embankment," according to the complaint.

The lawsuit alleged that Christal McGee, 18 at the time, was driving the Mercedes and using the Snapchat speed filter on her phone at the time of the crash.

"McGee wanted to post an image of herself going fast. She argued that she was, 'Just trying to get the car to 100 miles per hour to post it on Snapchat,'" the complaint said.

A passenger in McGee's car said she hit 113 mph on the Snapchat filter and the reading was 107 mph when the cars collided, according to the lawsuit. The speed limit was 55 mph.

The suit said McGee was negligent and so is SnapChat for refusing to delete a feature that it knows encourages risky behavior.

"It's an intersection of two choices," Neff told the Tampa Bay Times. "Drivers choose to drive fast to put it on SnapChat and SnapChat chooses to put this product out there. It's horribly dangerous to be goading these people to speed to get attention. If there's some other explanation for what this product does, I haven't heard it."

SnapChat did not respond to a request for comment Friday. In a previous statement to the New York Times about the Wentworth case, the company said "no Snap is more important than someone's safety."

"We actively discourage our community from using the speed filter while driving, including by displaying a 'Do NOT Snap and Drive' warning message in the app itself," the statement said.

Neff said the disclaimer doesn't absolve a company that knows its product is dangerous.

"We need to have this conversation because SnapChat doesn't care about one lawsuit," he said. "Some time in the not too distant future, they will care what a jury thinks."

The barely recognizable remains of Cortes' Volkswagen might lead to the conculsion he was moving at extreme speed but there are many more factors to consider, said Jeff Armstrong, a professional engineer in Lutz who specializes in forensic crash reconstruction. Armstrong viewed photos and video footage of the wreckage at the request of the Times.

"I've seen this kind of damage at speeds of 40 to 50 mph and at much higher speeds depending on variables like angle of impact," Armstrong said.

In addition to Cortes, those killed in the crash were his passenger, 19-year-old Jolie Bartolome of Lithia, and three of the people in the van — Marianela Murillo and two of her children, Maria, 10, and 9-year-old John. After colliding with the Sienna, the Volkswagen rotated and hit a Toyota Scion. Its driver, Carla Marie Wyman, 54, of Seffner, suffered serious injuries.

Murillo's 18-year-old daughter Lina Bernal and 15-year-old niece Luisa Louisa were also in the van at the time of the crash and taken to Tampa General Hospital with critical injuries.

Both are stable but neither is awake or alert, said a cousin, Mizrah Medina, 24, of Tampa. The family has seen the SnapChat video, Medina said, but healing rather than the crash is on their minds now.

"It's sad to see how it happened minutes before the accident, but I do send my condolences out to the other families as well," Medina said.

Times senior news researcher John Martin and Times staff writers Sara DiNatale and Anastasia Dawson contributed to this report. Contact Tony Marrero at tmarrero@tampabay.com or (813) 226-3374. Follow @tmarrerotimes.