Scientists are on a hunt to find the origins of mysterious tar balls that have washed ashore on Southern California beaches in recent weeks – and they think they're getting close to an answer.

"I think the answers are starting to come in," said David Valentine, one of the scientists testing tar ball samples, and a professor of Marine Science at the University of California, Santa Barbara. He said he's hopefully that within "several days" the team could start finding at least some of the answers.

But it's a complex and labor-intensive process, he said.

One of the big questions is whether the tar balls are related to the oil spill in Santa Barbara last month.