BELLINGHAM, Wash. -- The cough suppressant dextromethorphan was found at the Bellingham home where a 17-year-old and a 19-year-old died over the weekend, Whatcom County sheriff's deputies said.

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The substance, known as "dex," is used by some young people as a recreational drug, deputies said.

The victims were identified as Ryan Morgan, 17, who lives in the home and Cory Carlson, 19, a friend who spent the night.

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Morgan's parents found the two upon returning from church on Saturday afternoon and could not revive them. Morgan was a junior at Squalicom High School.

Investigators found what they call "significant quantities" of the dextromethorphan at the scene.

It can cause sudden death when consumed in the wrong doses or used in combination with other drugs or alcohol, according to a news release from the Whatcom County Sheriff's Office.

The Whatcom County Medical Examiner's Office has not yet determined the cause of death. Toxicology tests will take several weeks, the M.E. office said.