The Calaveras County coroner will conduct an autopsy Monday on an 8-year-old girl found stabbed to death in her family's home, an official said.
A cause of death for Leila Fowler could be determined as soon as Monday afternoon.
Leila's body was reportedly first discovered by her 12-year-old brother, who walked into their family home in Valley Springs and encountered his sister's suspected killer.
The assailant was described as a white or Latino man, about 6 feet tall with a muscular build, last seen wearing a black long-sleeved shirt and blue pants, authorities said.
The Calaveras County Sheriff's Department issued an update Sunday night in the case:
"The search for a suspect in this case has continued overnight and through the day today," the department said. "Overnight, sheriff's detectives and members of the California [Department of Justice] Bureau of Forensic Services executed a search warrant at the home where the homicide occurred.
"Evidence was collected at the scene, including fingerprints and what investigators believe is DNA. At this same time, detectives were conducting follow-up interviews with witnesses and family members."
Police said more than 100 law enforcement officers were on the case.
Authorities were conducting a door-to-door sweep of homes, checking storage sheds and horse stables and searching attics.
"It is a difficult area to search. It's rural, remote," sheriff's Capt. Jim Macedo said.
The grisly murder has put the quiet community of 3,500 on edge.
"A lot of us here are used to keeping our doors unlocked, our cars unlocked," resident Connie Brodie told the local CBS station. "I'm sure a lot of families last night locked all their windows, locked all their doors for the first time."
According to Fox40 in Sacramento, Mark Campbell, the area school district's superintendent, said in a statement Sunday:
"As we all grapple with the tragic and senseless loss of one of our own, we do so knowing that we will be ready to do what is necessary to provide a safe environment for students and for staff, and to stand unified and strong as we provide whatever level of support and assistance that is necessary to help the family, our students, our parents and our staff process the unthinkable."
Campbell added that counselors would be on hand at Jenny Lind Elementary, Toyon Middle School and Calaveras High School. There will also be an added law enforcement presence at Jenny Lind Elementary and nearby bus stops, according to Fox40.
Leila was one of seven children in her family, KCRA-TV reported.