Pfizer Inc.'s medical research lab in St. Louis County is missing $700,000 worth of gold dust, and police are trying to determine if it was lost or stolen.

The St. Louis Post-Dispatch ( http://bit.ly/UiPayr) reports that Chesterfield police began an investigation this week after a Pfizer employee conducting inventory couldn't find the gold dust purchased last year for use in research.

Police Capt. Steven Lewis says no one is "sure if they just didn't account for it and it was used naturally, or if it was stolen or misplaced."

Pfizer said in a statement it is working with law enforcement and takes the matter seriously.

It wasn't clear what purpose the gold dust has in Pfizer's research.

Chesterfield is about 20 miles west of St. Louis.

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Information from: St. Louis Post-Dispatch, http://www.stltoday.com