Officials with the Los Angeles Fire Department said the white Cadillac Escalade struck the house so hard that it went five to six feet inside the structure.
They were in the corner bedroom when the Escalade crashed through the wall.
Collision investigators say the 22-year-old father of the baby likely rammed his car into the side of the house on purpose. Authorities pointed to the lack of skid marks along the pathway of the crashed car as evidence that this was no accident.
"I just heard a big acceleration and next thing you hear is a big boom," said neighbor Tony Hernandez. "I ran out outside and I saw the truck in the house."
The infant was rushed to an area hospital, where she later died. The 19-year-old mother died at the scene. A relative at the scene identified the mother as Trudy Bonilla and the baby as Naomi Bonilla.
The driver of the SUV was treated at a local hospital for minor injuries. He was later taken into custody and booked on two counts of murder
Family members were at the scene and an uncle told Eyewitness News that the baby's father and mother were involved in a fight during a party held Sunday afternoon. The uncle said the father did not want to give the baby back to her mother, and he threatened to kill the baby, the mother and himself.
"They used to seem really happy," said neighbor Erika Tovilla. "I used to see the guy with the girl hugging and kissing. They were OK. We didn't see anything wrong with them, so we never saw this coming."
At the time of the crash, there were six children inside the home. At least four teenagers were in the same room as the victims at the time of the incident. The uncle said one of the teenagers was taken to the hospital with serious injuries.
The Associated Press and City News Service contributed to this report.