Police in this California surf city are looking for anyone who saw two teens before they were found dead in an apartment with an empty can of an alcoholic energy drink and traces of drug and alcohol use.

"We're trying to determine if there was anyone with them that evening, how they obtained the alcohol and what kind of drugs they might have used," Lt. Russell Reinhart said Monday.

The bodies of Aaron Saenz, 15, of Westminster, and Chelsea Taylor, 16, of Huntington Beach, were found Friday morning along with an empty Four Loko can and physical evidence of drug and alcohol use in the apartment, which was supposed to be empty.

When it was first sold, Four Loko contained both alcohol and caffeine, but its maker announced in November that it would remove the caffeine from its formulas. It was not known if the empty can found in the apartment contained caffeine.

The sale of Four Loko has been banned by at least 13 states through their alcohol control boards, according to the National Conference of State Legislatures. Last year, the Food and Drug Administration warned four companies that make caffeine and alcohol drinks that their products are unsafe.

The managers of the large apartment complex spotted two people in the apartment and called police, who found the bodies, Reinhart said.

"There was no indication of trauma, no weapon involved. So we believe these deaths were accidental or an overdose," Reinhart said. Autopsies were conducted on the teens Monday but the cause of their deaths remained under investigation.

Reinhart said it would take a couple of months until the toxicology tests confirm exactly how the two teens died.

He did not specify the drug evidence found because it could interfere with the investigation.

He said the boys' families did not want to speak publicly.

"It's obviously tragic," he said.