GRAND RAPIDS, Mich. (WOOD) A Grand Rapids mother faces arson charges after investigators say she set fire to her home with her children inside.

“This is a shockingly cruel, unimaginable crime committed by a mom against her three kids,” Grand Rapids Police Department Chief Eric Winstrom said at a Monday afternoon news conference.

Roconda Singleton, 46, is expected to be arraigned within days on charges of first-degree arson and three counts of second-degree child abuse in connection to the Saturday evening house fire on Eastern Avenue between Hall and Martin Luther King Jr. streets.

A 12-year-old girl remained in intensive care Monday at Helen DeVos Children’s Hospital in Grand Rapids, officials said. The fire chief said she suffered burns and smoke inhalation.

Two other children, ages 10 and 7, were treated and released from the hospital, according to a news release.

“This is a mom that meticulously took all seven of her smoke detectors and put them in a bag and removed them from the house before she poured lighter fluid all over the house and lit it on fire in an attempt to kill her three children,” Winstrom said.

He said Singleton poured lighter fluid “all over upstairs, all over downstairs.”

“I think she covered the couch in lighter fluid,” Winstrom said. “That’s a pretty effective way to start a fire.”

A passerby spotted the flames and called 911. Police body camera video released during the news conference shows an officer questioning Singleton about whether anyone was still in the house and then directing firefighters to a bedroom on the second floor. With huge, bright orange and yellow flames leaping from the first floor and smoke billowing, firefighters climbed a ladder to a second-story window to rescue the 12-year-old. Firefighters can then be seen laying her in the snow and starting chest compressions.

“Even when the firefighters were walking in the second floor in the back … the smoke (was) so thick that I’m sure you couldn’t see more than an inch in front of your face,” Winstrom said.

Grand Rapids Fire Department Chief Brad Brown said 42 firefighters from 13 units rushed to the hours to battle the fire, which he said advanced “very rapidly.”

“Our members placed themselves directly in harm’s way to save a life,” Brown said. “The vast majority of rigs in this city of Grand Rapids, at one point or another, made their way through this fire. … We had multiple things going at the same time. We had four separate teams searching, two different crews doing fire attack, ventilation, water supply and medical out in the front yard.”

The bag of smoke detectors, meanwhile, was in the backyard, the police chief said. He said they can be heard beeping in the bodycam video as officers moved by the bag.

If convicted of arson, Singleton faces up to life in prison. Each of the child abuse charges are 10-year felonies.

Singleton has a criminal history, but the police chief said it is not extensive and the home was not a “problem house.” Winstrom said he “cannot fathom any motive” for a mother attempting to harm her children. Kent County Prosecutor Chris Becker said “it’s a mental health issue.”

“I think that’s what’s going to come out,” Becker said. “But a lot of the calls that they were getting were mental health-related for mom. But there’s … no prior child abuse.”

The police chief said Children’s Protective Services is now involved and the children’s father who does not live with the kids and Singleton is “very much engaged.” Community members are also working to support the children.