Story highlights Samples of water in Hugo, Colorado, test negative in lab for THC

Lab tests were done after field tests had showed a positive result, now believed to be false

(CNN) A Colorado town's marijuana-in-the-water mystery didn't check out after all.

Laboratory testing showed there is no THC -- the principal psychoactive chemical in cannabis -- in the town's water supply, contrary to what field tests had shown earlier this week , the Lincoln County Sheriff's Office said Saturday.

The announcement brought the curtain down the town's two-day water advisory, during which its 700 residents were asked not to drink, shower with or cook with the tap water.

"We are happy to announce that the water advisory is canceled immediately," the sheriff's department said.

#HugosWater CBI Scientists have concluded water samples are NEG for THC. Believed that test kit were false +. Water advisory is cancelled!!! — Lincoln County S.O. (@LincolnCountySO) July 23, 2016

Why did investigators think THC was in the water to begin with? It's a tale that begins with an employer's drug tests.

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