Police in Northern California are studying forensic evidence, reviewing old missing person cases and reaching out to medical schools to try to solve a mysterious body parts case.

Two arms, a leg and a head were found near a river over several months, with the most recent discovery last weekend. 

California Department of Justice considers the case a priority and is running DNA samples and fingerprints tests in a desperate attempt to figure out exactly who the body parts belong to and if they came from the same body, Sutter County sheriff's Lt. Butah Uppal told FoxNews.com. 

Uppal said there are no indications someone is randomly going around cutting of limbs, because they don't have a large number of missing persons cases. They are, however, cross-checking those lists as they get more information about who the body parts may belong to. 

"We don't know what's going to come out of it," he said, adding they've checked with surrounding universities and laboratories to see if there were any reports of missing body parts. They've come up empty so far.

The head and two arms were discovered last weekend along the Feather River, about a half-a-mile from where a leg was found in November. 

Forensic tests revealed the arms are possibly that of a male over the age of 45. The head is believed to belong to a white male, but that could not be fully confirmed yet, police said. 

Previous DNA tests on the leg show it belongs to a male and is believed to have been surgically removed. 

"Evidence shows it was surgically removed or done by someone who has experience in removing limbs," Uppal told FoxNews.com. 

Uppal said it is too early to say if all the body parts are connected to the same person. 

The leg was found in a plastic bag, but Uppal wouldn't say if any of the new parts were found the same way, as to not compromise the case. 

Uppal is hoping when results from the fingerprint tests, it will give them more clues. The tests can take up to a few weeks to complete.

"We want to try to find out who this person is and reunite them with their family and bring with it some justice," he told FoxNews.com.