The woman's husband, 40-year-old Ruben Fregoso, is a person of interest in her death. He is also the father of the girl and is accused of abducting the child.
Fregoso and his daughter, Daleza Fregoso, were last seen Sunday morning near Alsace Avenue and Ferndale Street. An Amber Alert was issued for the missing girl.
Marysol Garcia, the child's mother, was found dead inside her West Adams home Monday after police were called to conduct a welfare check.
"It's been terrible what's happening," neighbor Martha Guerro said at a candlelight vigil held for the mother.
Investigators believe Fregoso has taken his daughter to Mexico where he has family. His vehicle was found near the border, but there were no signs of the father and daughter.
Neighbors say the 5-year-old was the light of the neighborhood.
"The girl was so sweet, so young," neighbor Carrie Coleman said.
"I'm hoping that the baby didn't see anything that could scar her for life," Coleman added. "My prayers are just with the family."
As loved ones mourn Garcia's sudden death, they are rallying around her 14-year-old daughter, who is desperate for her little sister's safe return.
"We're hoping that they can find him and bring the little girl back because the sister needs her," Guerro said.
Authorities continue searching for the father and daughter.