Updated

The gunman was calm one moment and frantic the next. For 23 hours on Thanksgiving Day, police said, officers tried to pacify Lance Johnson — who had a history of mental illness and a criminal record — and persuade him to release his neighbor Tasha Cooks, whom he'd taken hostage in an apartment building.

The standoff ended early Friday when Johnson, 21, fatally shot Cooks and then himself, leaving Cooks' family to question whether police did enough to save her.

It began around 1:30 a.m. Thursday, when Johnson apparently became irritated by a noisy child in the building, then became "combative," police said.

He fired shots at a door in the building, but no one was injured, police spokeswoman Monique Bond said. Six people thought to be in the apartment with the child fled.

Around 2:30 a.m., Johnson took Cooks hostage in her second-floor apartment.

Then everyone — police, family, neighbors — began to wait.

As the standoff dragged into the night, Cooks' frustrated relatives yelled at officers over the yellow tape that cordoned off several blocks in Chicago's South Shore neighborhood, demanding police act more swiftly to rescue Cooks.

But police said Friday that Johnson was unpredictable. He hadn't taken his medication and he threatened to kill Cooks, they said. He also told police he had two hostages when he only had one.

"He was going in and out of different behaviors, which is why the situation was never stable," Bond said.

Police said they negotiated with Johnson by phone. At one point, they delivered cigarettes and soda at the gunman's request.

Cooks used the apartment's phone to call her great-grandmother earlier in the day, family members said. Her brother Donzell McKinzie, 23, said she told them she was being beaten by her captor.

"That was the last time I heard ... her, and she said she didn't want to talk anymore," McKinzie said.

SWAT team members rushed the apartment when they heard a gunshot around 1 a.m. Friday, police said.

Johnson was arrested in 2002 for unlawful possession of a weapon and had a lengthy criminal history, Bond said.

An autopsy on his body was planned for Saturday, officials said.

His family, who helped police with the negotiations, asked not to be named and declined to give details about him.

Cooks' family said she was a nursing home worker who often took care of her 14-month-old brother, Darrell.

"She was a very bright young lady and very caring," said her aunt, Sherry McKenzie. "Right now, I don't even have the words. I'm still worked up about the situation. ... I really would like to know what happened, really."