The initial autopsy of the dead infant found Monday in a Roseville park revealed the sex of the child - a girl - but no easy answers about the cause of death.
"It doesn't show traumatic injury," said Darin DeFreece, a detective with the Roseville Police Department.
Further tests will take time, he said.
The baby, with the umbilical cord and placenta attached, was found wrapped a blanket and plastic bag shortly before 8 a.m. Monday near the wooded bike trail area of Saugstad Park, which is west on Interstate 80 and on the south side of Douglas Boulevard from Royer Park.
Officials noted that state law allows parents to surrender a child without fear of prosecution at approved locations.
Under the law, 407 newborns have been safely surrendered, from Jan. 1, 2001 to March 31, 2011, according to the California Department of Social Services. During that same period, another 151 newborns were found alive after being illegally abandoned at non-approved locations.
Anyone with information about the incident is encouraged to call (916) 774-5070.