A homeless man had beer poured on him before behind pushed into a canal.
Footage of the attack shows the victim asleep on the ground next to a brick wall.
He is woken by the two men filming the incident in what appears to be Birmingham canal, the Birmingham Mail reported.
One asks him: "Yo, big man, wagwan? You alright? What you drinking? Come on bro, wake up," before beer is poured over his head.
The empty can is then thrown at the man as he struggles to get to his feet.
The camera moves away for a second, losing sight of the victim while he is seemingly pushed into the canal.
It pans back and he can be seen immersed in the water.
The video ends with the two men laughing and the words: "You're cold, you're cold."
Sergeant Dale Quiney, of Birmingham police, said: “We’re aware of footage on social media showing a man being pushed into a canal in Birmingham.
"While it has not been reported to us, we have identified the victim and will be making contact with him to get further details.
“This is a really nasty attack on a vulnerable member of the public and I’d urge anyone who saw what happened, or who knows the names of those involved, to do the right thing and get in touch with us."
Police later said they believe the incident took place around three months ago just north of the city centre.
A police spokesperson added: "We believe we have identified the victim. It's understood he's been seen several times since the incident, most recently earlier this month. Enquiries are on-going to identify the offenders.
"Anyone with information is asked to contact us quoting log 2276 from 21 July."
Social media users reacted to the video with one on Twitter branding the men as "absolute vermin."
Another wrote: "That’s just awful, why oh why would you do something like this?"
Police have asked if anyone has any information to please get in touch through Live Chat at www.west-midlands.police.uk, via 101, or Crimestoppers, anonymously, on 0800 555 111. Quote log 2276 of 21 July.
