"I need a fire truck at Harrisburg Lane," said the voice on the phone. "There's a fire underneath our trailer."
Someone inside spotted flames outside the mobile home. The front, side and back doors were doused with gasoline.
The three adults inside scrambled to get out, including a mom with her three kids.
Now Kayla Zorn is behind bars and facing assault and arson charges.
"She was trying to make sure they were trapped in there," said Mike Vandewiele, a neighbor. "She was twisted up about something."
But what would prompt anyone to torch a house while people and children are inside of it?
"One of the males in the house indicated he was having trouble with a past relationship," said Police Chief Brad Kersten. "It appears as though there was definitely some planning in the process as to how she was going to go about this."
Zorn was the woman scorned.
Police say she was bitter about a romance that fizzled and her ex-beau announcing a new flame on Facebook.
Zorn not only tried to burn the house but camped out across the street to watch her handiwork, according to investigators.
"The arsonist was standing not five feet from me," said Vandewiele. "Right on the side of my porch acting like she was one of my other neighbors.
"She was watching it. She wanted to watch it burn."
Thankfully her ex-boyfriend and Chesterfield police kept the flames from spreading.
Police found Zorn's truck a block away from the house. There were half empty gasoline cans in the bed.
"The officers then patrolled the area on foot and they located the suspect," Kersten said.
And police say she could not come up with a good reason why she reeked of gasoline.
Kersten says Zorn admitted to trying to burn the house and that's not all.
"It appears as though she did know the house was occupied by the ex boyfriend and other occupants in the house at the time - including children," Kersten said.