SALEM, Mass. (AP) — Blood and lighter fluid stained Tanicia Goodwin's clothes and slash wounds marked her neck when she walked to a police station, smashed a display case in the lobby and collapsed to the floor.

Minutes earlier, Goodwin had slashed both her children's throats, soaked them with lighter fluid and set their Salem apartment on fire, prosecutors and emergency officials said.

But Goodwin didn't initially tell police much Sunday night.

"I did what I had to do to protect my children. I'm sorry," Goodwin kept repeating to a police interviewer, according to authorities.

Her 8-year-old son, Jamaal, was more specific after a firefighter found him, though he couldn't talk and was struggling to breathe.

"The paramedic asked if his mother did this to him, and he nodded yes," prosecutor Melissa Woodard said at Salem District Court on Monday.

A firefighter found Jamaal sitting by a door in the burning apartment, and his 3-year-old sister, Erica, was left face down and bleeding in a nearby unit, Salem fire Chief David Cody said. Jamaal was in critical condition on Monday and Erica was in stable condition after they underwent surgery at Children's Hospital in Boston, officials said.

Goodwin, 25, was ordered held without bail and scheduled to appear in court next week. A judge will then decide if she's eligible for bail on charges including two counts of assault with intent to murder and arson.

Goodwin pleaded not guilty. Her court-appointed attorney, Steven Van Dyke, didn't immediately return a call seeking comment Monday. No motive was disclosed by the prosecutor or Goodwin's lawyer.

Later Monday, several residents outside the building where Goodwin lived at the high-rise Salem Heights Apartments declined to comment. The door to Goodwin's building was locked to non-residents.

Prosecutors said Goodwin not only set the fire but also disabled the apartment's smoke alarms, removed the interior doorknob and blocked the vents and nearly every sprinkler with duct tape.

"Almost everyone has asked that same question: 'What went through her mind?'" Cody said.

Firefighters responded to the blaze Sunday night and saw Goodwin and her daughter with two other adults in a neighbor's apartment. But they didn't notice the girl was wounded as they headed to the fire in Goodwin's apartment, Cody said.

He said Lt. Richard Arno used a hallway extinguisher to knock down the fire enough to get a look around. Soon after, he found Jamaal sitting against a wall with a neck wound so severe his trachea was exposed. Arno carried the boy out, and firefighters put out what turned out to be a minor blaze.

Firefighters then checked the floor to make sure everyone had left and found Erica had been abandoned on a couch in the neighboring apartment, Cody said.

"It was basically just going back and checking everything, and they just happened on the girl," he said.

Prosecutors said nurses had to wipe lighter fluid off both children before they could be treated.

Three cans of lighter fluid were found around the apartment, as well as a large kitchen knife, which police believe was the weapon Goodwin used, prosecutors said.

After leaving her apartment building, Goodwin apparently walked to the police station, about a mile away. While she was being interviewed, Goodwin asked for a cigarette, but police wouldn't give her one because she also had lighter fluid on her clothes, authorities said.

Later, she took off all her clothes in an interview room, according to the report. Police gave her hospital scrubs, which she appeared to be wearing in court.

While speaking with police, Goodwin indicated that she had intended to kill herself, though her neck wound was "much more superficial" than her children's, Woodard said.

"I'm not supposed to be here. ... I'm not supposed to be alive," Goodwin told police, according to the police report.

After her son indicated that Goodwin had attacked him, police asked Goodwin, who is not married, if her husband or boyfriend had attacked her and her children.

"She shook her head no," Woodard said. "When asked if she had hurt her children, she shook her head yes."

Goodwin asked about the welfare of her children several times, the police report said.

"Thank you, God. Please keep them alive," she said.

"I just want to protect my babies. Mama loves you," she said later. "I wish I were with you right now. ... I'm so sorry, Erica, Jamaal."

Goodwin regained custody of Jamaal in 2010 after voluntarily giving him up to a cousin in 2007 so she could earn her GED and college degree, the Boston Herald reported, citing probate records.

Goodwin petitioned to bring Jamaal back to her home after her cousin planned to move with him from Rhode Island to Georgia.

"I feel without a doubt my situation is much more stable then (sic) when I relinquished custody of my son," she wrote.