SANTA ANA, Calif. -- Air quality investigators have confirmed that a foul stench that stretched across Southern California came from the Salton Sea.

Officials from the South Coast Air Quality Management District said in a statement Tuesday that collected air samples have given solid evidence of what they already expected: A huge fish die-off at the saltwater lake 150 miles southeast of Los Angeles combined with winds to create the sulfur-like smell that people across the region reported Monday.

The air samples showed that hydrogen sulfide levels were highest around the lake and grew weaker at longer distances, and modeling showed the smell could have traveled a fairly long distance in Monday's weather conditions.

Investigators also ruled out other possible causes like landfills or oil refineries