Narcotics police on Long Island say two men advertising "pain relief" online were actually selling heroin.

Daniel Bigelow (left) and Gustavo Arce-Giron (Nassau County Police)

Two men from Elizabeth, N.J., were arrested Monday afternoon in Bethpage, N.Y. They face charges of criminal sale and possession of a controlled substance.

Nassau County police say Daniel Bigelow and Gustavo Arce-Giron placed an ad on Craigslist for pain relief for sale.

Undercover detectives contacted the telephone number in the ad and arranged a meeting. That's when police say they bought 40 bags of heroin from the duo and arrested them.

It was not immediately known if the men are represented by attorneys.

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