Friends say the victim was a 30-year-old transgender female who went by Dominique.
"Dominique was a good person. [She] just gave my son a car. Dominique was real nice," said Latonya Ward, the victim's friend.
Police responded to the apartment on Bennett Ave around 4:30 p.m. for a domestic dispute after neighbors reported hearing sounds of a struggle.
"I heard there was a lot of commotion in her place and she was screaming and hollering for help, begging for her life," said Ward.
When officers arrived, they found the front door unlocked and the 30-year-old dead inside.
"We have witnesses that say they saw a male leaving the area of the apartment, a black male, loading items into the victim's vehicle and then driving away," said Sgt. Jim Burton with the Fontana Police Department.
The car was described as a black 2004 Mercedes-Benz C240 with the California license plate 7AAY925.
Authorities don't have a solid description of the suspect or a possible motive, but neighbors say they had suspicions.
"We figured something was going to happen when strange people start showing up and somebody's going to get hurt one day, and it happened today," said neighbor Gerald Hewlett.
Investigators say it will be up to the coroner to determine how the victim died. Friends say they have no idea who would want to hurt Dominique or why.
"I'd like to see justice be served. It's unfortunate to see somebody just brutalized in that manner to which they lose their life. It's uncalled for and it's unjust. I'm sure on behalf of her friends and family that we want to see the killer prosecuted to the fullest extent of the law," said Jordan Boatwright, the victim's friend.