ISIS executes Shiite law enforcement for "apostasy." Islamic State Saladin Province Media House

In the latest chilling warning to Iraqis who might stand in their way, the Islamic State group on Monday released photos purporting to show a mass execution in Iraq. At least seven Shiite men were shot after the militants accused them of working with the Iraqi army to combat the militant insurgency in the province of Saladin, north of Baghdad.

The series of photos, titled “Day of Retribution,” followed what has become a sickening trend in the militant group’s execution propaganda, with ISIS members dressed in black with their faces covered and the victims wearing orange jumpsuits. The final photos show 11 militants holding pistols in front of an ISIS flag.

The tweet says, "We got rid of a network of Shiites working for the Safavid government (and they were cringing and repenting)". The term Safavid, referring to a Persian imperial dynasty, is used by ISIS to refer to Shiites and to the Shia-led Iraqi government, which enjoys the support of Iran.

ISIS identified two of the men as Shiites and colonels in the police who had “repented” but continued giving information about the militants to the Iraqi armed forces and Iraqi government. One was accused of passing on locations of impending ISIS bombings to the Iraqi army. Another man, who was shown close-up before being executed, was identified as a captain in the Iraqi police force and accused of returning to work for the Iraqi government after “repenting.”

The Sunni militant group, also known as ISIS, published the photos through its local media hub for the Saladin province in Iraq, which means the propaganda was aimed at a local audience.

When ISIS entered Iraq last year, militants executed thousands of Shiites, whom they consider “infidels.” However, this latest execution underscores an emerging trend in ISIS brutality as the militants continue to consolidate their territory.

The group has begun a relentless campaign of violence against those who question its authority and those it considers to be spies for Iraqi and Kurdish forces. This is also an attempt to discourage others from provinding information against the Islamic State to the Iraqi army and to encourage defections from the Iraqi armed forces.

According to Jasmine Opperman, a South Africa-based analyst at the Terrorism Research and Analysis Consortium (TRAC), “The IS will use any tactic to ensure that their ideology is imposed and adhered to -- the brutality is likely to see a more internal focus with those opposing the IS.”