The macabre spectacle began last week amid the groves and thickets along the banks of the Tigris river, the only place that people have to relax and ease the tensions caused by the IS occupation of Iraq's second-largest city.
A large number of young people, children and families gathered at the site waiting to see the programme that the extremists would deliver on big screen monitors that had been installed for the purpose.
After the curtains were drawn back, hymns were sung encouraging people to join the Sunni jihad movement and, in particular, IS, which has occupied large swaths of Syrian and Iraqi territory. Then, viewers were horrified to see scenes of various bloody slayings by IS executioners, including beheadings and murders of hostages and prisoners of war.
The video that shocked most people showed the execution of British journalist David Haines, who was slaughtered by a hooded man with a knife.
"The bloody scenes my family and I have seen are unbelievable. My little son, four years old, asked me: 'Dad, why is this man slaughtering that person?' What I heard from my son left me shocked, I didn't know how to respond," Mohamed Sobhi Jarallah told Efe news agency.
Militants showed James Foley's beheading video
For Jarallah, a 34-year-old resident of Mosul, IS is showing the videos "to convince others that beheading, murder and abuse are what awaits those who oppose them". "Their real goal is to terrorise," he added.
A spokesman for the IS, Abu Mohamed al-Adnani, called Monday for the indiscriminate murder of citizens of countries that have joined the alliance led by the US to fight the militant group.
Columnist and sociologist Emar Jafar said the methods used by jihadis were an attempt to get Mosul residents used to the way they operate. "They also recruit children and women for the same project. Terrorism is being shown on the screen. That will also serve to dissuade people of any intention to recover their freedom," Jafar said.
"IS understands that movies increase terror among the people of Mosul and remove the last hope left to them, as well as any thought of resistance," the sociologist said. Activist Mohamed Hashem also noted that the extremists have recently opened information centres in many parts of Mosul, especially in the most populous areas.
The centres are managed by three or four people wearing an Afghan-style uniform, distributing pamphlets and instructions issued by the Sharia court established by the group to implement its radical version of Islam.
The information centres feature large screens on which they show the military operations undertaken by the IS in various regions of Iraq. The organisation tries to win people's support so as to recruit volunteers to fight in their ranks, especially teenagers and children, owing to the high unemployment rate in Mosul, Hashem said.