Scroll through the slideshow for more photos videos on the investigation, including the West Allis press conference held Friday afternoon.
WEST ALLIS - West Allis Police and Fire have confirmed the victims in the fatal fire Thursday night were two four-year-old boys and one five-year-old girl.
According to police, there were no adults home at the time of the fire, and the mother is currently in custody.
The police and fire departments in West Allis responded to the fire at a home near the corner of South 77th and West Hicks Streets just after 5:15 p.m. Thursday night.
"West Allis Fire Department personnel worked to extinguish the fire and investigators from the West Allis Police Department are assisting to determine the cause and origin," said Acting Chief Charles Padgett with the West Allis Police Department.
Padgett said they can confirm three people found dead inside the home, but they do not yet know the cause of the fire.
The original statement from police said there were four people inside the home, but Padgett later said that "rescue personnel confirm three. Due to structural instability rescue personnel (were) unable to safely reach all areas inside at this point."
Fire Chief Gary Streicher told Newsradio 620 WTMJ's Jon Byman that crews found a hole in the bedroom and significant damage throughout the home.
TODAY'S TMJ4's Nick Montes reports that a family lived in the rental property.
The fire is still under investigation. On Friday, we could learn the identities of the people who died.
This is the second deadly fire in the area in less than a month, and the chief said he'd be helping his staff through the mental stress.
Check back for more information on this story as details come in to us.
Jon Byman, Cody Holyoke, Nick Montes and Lacey Crisp contributed to this story.