Based on items found on the property like clothing and a blanket, police believe the mother may have at one time lived on the property, but so far, no one has been charged.
Police said a dog found the remains between two houses on Monday morning, and so far, there is no evidence to suggest the body was buried.
Police have been unable to identify the sex or race of the baby because it was so badly decomposed. Police are also unsure how long the baby had been dead. They are working to find the parents of the infant.
Click in the Eyewitness News story window above to watch the Ellen Frere's report from the scene.
Neighbor Jesus Vega said he thought it was a doll at first when he looked out his window. His neighbor, who lives on the property where the body was discovered, told him it looked like a newborn.
"The dog that belonged to the property here was lying next to the baby on the ground," said Corp. Jose Gonzalez of the Santa Ana Police Department.
"There is an alleyway that is accessible from the rear of property, so it is quite possible someone may have disposed of body by simply throwing it over that fence," Gonzalez said.
Neighbors said one family owns both homes, and a number of family members live in each house. Authorities questioned family members Monday, but they told police no one was pregnant, and they did not know how the baby got there.
Anyone with information is urged call the Santa Ana Police Department at (714) 245-8665.