3 Young Boys Perish in Blaze After Grandfather's Ex Allegedly Torched Their Home: Cops

Three young boys perished in a Florida house fire over the weekend after cops say their grandfather's ex-girlfriend set fire to his home.

Marian Williams, of Bartow, has been arrested and charged with first-degree murder among other counts after a fire killed the boys, all of whom were reportedly age 10 or younger.

Read: Firefighter Dies in Crash on His Way to Fire That Killed 2-Year-Old

Investigators say 49-year-old Williams set the home on fire intentionally. Rescuers got the call in the pre-dawn hours Saturday.

"It's unthinkable. You know I can't imagine what it would be like if my children died in a fire," a neighbor told WINK.

Their grandfather was pulled from the home and is reportedly recovering in a hospital.

A memorial with balloons and bears now decorates the burned out home, where the kids were visiting their grandfather for the weekend.

"It’s almost incomprehensive that a human being could do something like that, knowing that there were occupants in the house," a neighbor said.

Read: Mom of 2-Year-Old Twins Who Died in House Fire as They Were Home Alone Pleads Guilty

Williams was reportedly arrested just the day before the fire on battery and burglary charges before bonding out that same day.

She is being held in jail with no bond on three counts of first-degree murder.

Watch: Arsonist Accidentally Catches Fire, Causing More Damage to Himself Than Business