PINECREST, Fla. -

The video showing an Islamic State militant threatening to kill a Miami Heat fan from Pinecrest was still haunting South Florida this week. On Thursday, the militants posted another terrorizing video.

The YouTube video of a massacre in Syria comes a day after, a United Nations report. U.N. investigators accused Steven Sotloff's kidnappers of "unimaginable brutality" in the country where the University of Central Florida alumni went missing from last year.

The Islamic State used social media to report that they had stormed an airbase Sunday and captured the Syrian government's soldiers and officers. The video showed dozens of men in their underwear running to be executed.

"The dead numbered 250," the YouTube video's caption said. YouTube removed it.

A day after the report said Syria had become the world's worst humanitarian catastrophe, the Islamic State released the YouTube video showing bodies lined up and another pile of bodies nearby. There was no sign of the compassion that South Florida was hoping for.

U.N. investigators also accused Islamic State militants of turning the city, where Sotloff disappeared, into a horror movie with their "brutal" governance methods.

"Executions in public spaces have become a common spectacle on Fridays," the report said.

Militants beheaded or shot people in the head at close range, according to the report released Aug. 27. Bodies were placed on public display -- often on crucifixes -- for a few days. Heads were displayed on sticks. That is what U.N. investigators concluded after 480 interviews and reviewing evidence from Jan. 20 to July 15.

Detainees were held in overcrowded Islamic State prisons. They didn't have access to lawyers and were beaten during interrogations, the report said. In areas the Islamic State controls, a violation of Islamic law could result in an amputation.

"Men have been lashed for smoking, possessing alcohol, trading during hours of prayer and failing to fast during Ramandan," the report said. Militants flogged a man for accompanying a woman they thought was "improperly dressed." Women who didn't cover their face and hair were beaten or lashed. 

The U.N. said Sotloff is one of many people, who have disappeared in Islamic State territory. Another example in the report was Italian Jesuit priest Father Paolo Dall'Oglio, a peace activist who vanished last year. An Islamic State defector said militants shot the priest dead, after his capture.

There was no mercy for children either. Islamic State militants "established training camps to recruit children into armed roles under the guise of education," the report said. It also said they deployed children on suicide-bombing missions.

An extreme militant group that branched off the Islamic State, released Peter Theo Curtis, of Boston,  to a U.N. representative. The 45-year-old writer had been held hostage for two years. 

"We join his family and loved ones in welcoming his freedom," but "hold in our thoughts and prayers the Americans who remain in captivity in Syria," National Security Advisor Susan Rice told NPR.

After the YouTube video of the massacre was released, President Barack Obama said that his administration does not have a strategy to combat the Islamic State militants. He said he dispatched Secretary of State John Kerry to work with allies and said he is considering military action.

"I will always do what is necessary to protect the American people," Obama said.

While the video was released on YouTube and Obama spoke about the possibility of military action, Islamic State militants and their supporters were on Twitter. They were using propaganda hash tags -- "Steven's head in Obama's hands" and "I.S. warning to Obama administration."

During his statement, Obama did not mention Sotloff, or his mother's plea.  There were also no public signs of compassion from the Islamic State toward Sotloff or his family on social media.

DOCUMENT | Download the United Nations Report released Aug. 27

ON THE WEB | Photos of alleged massacre of 250 (Graphic Content)

ON THE WEB | Portions of video of alleged massacre (Graphic Content)