Security cameras showed Margaret Reed walking down the back stairs of a Rogers Park apartment building Thursday, and then bolting up the staircase moments before the building burst into flames, Cook County prosecutors said.

As the flames spread through the building, Reed went to the home of an unnamed witness, and “demanded to turn the TV on because a fire had ‘just occurred down the block,'” Assistant State’s Attorney Maurice Alayo said at a bond hearing Friday at the Leighton Criminal Courthouse.

The fire was all over the news. Smoke and flames so terrified, 51-year-old Maria Silva, she  jumped from the window of her fourth-floor apartment trying to escape.

Police officers arrived at the burning building in the 1700 block of West Touhy just as Silva leapt, and watched fall to her death on the sidewalk below, Alayo said.

Police officers rushed into the building, trying to warn other residents, and found a 66-year-old woman, who had injured her leg stumbling out of her apartment in the smoke.

Reed, who could be heard shouting in the hallway outside the courtroom as she was led in by deputies on Friday, muttered and made faces as Alayo read a proffer of the evidence against her.

Judge David Navarro warned her to stop the grimacing at future court appearances, and ordered her held without bond.

Reed faces charges of first-degree murder and aggravated arson.

“You may take issue, you may contest the facts the state is offering,” Navarro said, peering down at Reed. “But to scowl and make faces and be mouthing words to the court…you should not do that at future appearances.”

Alayo offered no motive for the crime. Surveillance video showed that Reed was the only person who entered the stairway during the five hours before the flames erupted, Alayo said, noting that there was no other way into or out of the basement laundry room of the building. The cameras did not capture Reed setting the fire, Alayo said,

Investigators said the fire was “open flame to available combustible material,” Alayo said.

Neighbors identified Reed as person on the surveillance video, and police officers found clothing and a hat that matched what Reed was wearing in the video when they arrested her at her sister’s house.

Reed, 44, had multiple arrests for prostitution, Alayo said.

Reed lives with her sister and four children in an apartment about three miles from the scene of the fire, Assistant Public Defender Sandra Parris said.

Two women who apparently were related to Silva sat in the the courtroom gallery, but declined comment.