The couple were spotted on the middle of a crowded train platform, the woman crouched between the man’s legs.
A furious passenger snapped a photograph of the duo (neither of their faces were in shot) and posted it to Facebook, in a bid to catch the attention of the Massachusetts Bay Transportation Authority.
She wrote furiously:
Dear #MBTA,
I understand you are having financial problems and it is difficult to maintain a broken system.
*However, my tax dollars should be going to pay your police force because I shouldn't have to stand next to a man receiving oral sex, nor should I be ignored when I text and tweet the incident to the #MBTATransitPD. *
Get your s**t together.
Sincerely,
Can't unsee what I saw today
The image quickly went viral, with over 3000 sharing the NSFW snap.
And, realising that it hadn’t gained much attention from authorities, one social media user tweeted it directly at the MBTA.
It seems as if that has done the trick, as the Transit Police are now launching an investigation to track down the raunchy couple.
Speaking with Cosmopolitan.com, Transit Police Lt Richard Sullivan said: “We share the general public's disgust in the photograph.
“Thankfully a young child did not happen by the act and although the reporting party was the only witness to the incident we will not tolerate conduct (under Massachusetts General Law-Criminal and felonious) such as this on the MBTA.“
They continued: “The MBTA is a very safe public transportation system and we will exhaust all resources to identify, locate and arrest the individuals who were involved.
“This is an active investigation and we will update as appropriate. Thank you.”
If the couple are found, they could find themselves sentenced to up to three years in a state prison.
They may also be forced to go before the sex registry board.
SEX IN PUBLIC: THE COUPLES WHO GOT BUSTED [NSFW]
Sex in public: The couples who got busted [NSFW]
1 of 16The Clock Tower Couple - Sydney, Australia
This stark naked couple were photographed having sex on a clock tower in the middle of a busy shopping centre, and were seemingly unbothered about the terrifying drop they faced should they accidentally bump 'n' grind right off the balcony.
Ah well, live while you're young and all that…
2 of 16The Motorway Couple - Google Street View
It’s entirely possible that this couple isn’t actually having sex, and is rather just having some fun at Google’s expense. On the other hand, it’s also possible that they’re doing both. Either way, they're smiling - and that's the main thing, right?
3 of 16The 'New Mexico State Police Officer' Couple - America
This police officer was awkwardly caught out having sex, while in uniform, in public, in broad daylight by a security camera. Inappropriate use of time and tax money? Or just an excellent example of multi-tasking? You decide.
4 of 16The Russian Fountain Couple - Leningrad Street, Russia
This erotic encounter was filmed by 26-year-old Aleksey Douhov as the lovebirds went at it for 15 minutes on top of the historic fountain in the city of Samara, with the video quickly becoming one of the most watched on Russian social media. The ultimate PDA?
5 of 16The Parisian Couple - Paris
Where better to get down 'n' dirty than on the streets of Paris, City Of Love? Exactly.
6 of 16The Sex On The Beach Couple - Florida, America
Elissa Alvarez, 20, and Jose Caballero, 39, had sex on a Florida beach for a full 25 minutes before wandering off for a swim. Despite the fact everyone around them knew what was going on, nobody rang the police.
But, when the duo decided to go for round two, it became too much for nearby witnesses - one of whom was sitting with a 4-year-old girl.
7 of 16The Student Couple - Cambridge, UK
The guy who filmed this couple going at it on the streets of Cambridge told a local paper: "I heard some groaning outside and to be honest I thought it was some kind of a monster. I opened up the curtain. I could not really believe what I was seeing.
"I got all the guys over to have a look and I thought I better film this. It was pretty hilarious.”
8 of 16The Car Park Couple - Bluewater, UK
Kent999s - who pride themselves on telling the public what Kent's emergency services are up to - tweeted photos of a couple, whose trousers are halfway down their legs, passionately kissing while leaning against a black Citroen in the Bluewater Shopping Centre's carpark.
Blue by name, blue by nature, we guess!
9 of 16The 'On The Road' Couple - Magaluf, Spain
The couple, who can be seen having sex between two parked cars in the footage, were filmed by someone recording through a nearby window. During the two-minute encounter, the copulating couple - who appear to be in their 30s - seem unfazed by passing cars.
We guess they were a little distracted…
10 of 16The 'Should Probably Be Teaching' Couple - Slovenia
A married headmaster was found by students between the legs of a female maths teacher when they heard noises coming from a classroom.
They said: "We heard the noises and knew someone was having sex in there’ said one 19-year-old at the high school in Slovenia.
"But we thought it would be other students. We couldn’t believe it when we saw our maths teacher and headmaster."
11 of 16The Banking Couple - Oviedo, Spain
This impatient man and woman were busted by police when they stripped off and had sex inside an ATM bank. While they weren't arrested, they were made famous when photos of the incident went viral on Twitter.
12 of 16The History Loving Couple - Newcastle, UK
These history buffs were caught IN the buff when they were snapped on top of a fortification in Newcastle, England. Their photo soon went viral on Twitter and history was made.
13 of 16The Daredevil Couple - Tartu, Estonia
It must have taken a LOT of guts for these exhibitionists to clamber up on top of this bridge, which stands at 45 metres tall. Zoinks! Eyewitnesses photographed the couple and posted them to a Dutch social media site, which was nearly shut down when so many people logged in wanting to see it.
14 of 16The Student Couple Part II - University of Southern California, America
These two students decided to sneak onto the roof of their university for a steamy hook-up, and were snapped by hundreds of students standing in the quad below. Awks.
15 of 16The Sports Fan Couple - Yankee Stadium, America
In a YouTube video posted on the sports blog Deadspin, fans can be seen watching as a man clad only in a hiked-up CC Sabathia T-shirt and a woman had full-on sex in a Yankee Stadium Bathroom.
“People were jockeying for position outside the stall to take pics either over or under, and even standing up on the toilet bowl on the neighbouring stall,” one eyewitness said.
16 of 16The Katie Hopkins Couple - A field, UK
Yes, Katie Hopkins got photographed having sex in a field. Old news.