In the video suspects are sat in darkness on the floor cross legged with no space in between one another.
Some of them are heard coughing and others try in vain to cool themselves down by fanning some paper.
A few are wearing vests but some have no clothing on at all as temperatures hit well over 45C.
Where there is no space left on the floor, others resort to squeezing themselves onto a ledge around the wall.
Human Rights Watch visited a detention centre facility in Mosul and said the conditions were “horrific and inhumane”.
A senior Iraqi researcher told RT: “There were rampant problems of ill-treatment, of disease.
“In fact, there were multiple men that were dying in detention because of the sanitary and hygiene conditions in these facilities.
“The temperature was almost a hundred degrees Fahrenheit.
“The stench was immense, with men not being allowed to shower, no bathroom besides a toilet in the room.”
She said one cell she had visited was just 4 x 6 meters and claimed 114 men had been in there for months.