At least 16 people have died in the Pakistani city of Lahore after drinking what police suspect to be toxic cough syrup, BBC News reported.

According to police, the people who died were mostly drug addicts, who were most likely using the over-the-counter medication to get high.

"Some of the victims were found dead in a graveyard where addicts used to take different kind of drugs," Atif Zulfiqar, a local police chief, told Agence France-Presse news.

In order to find the source of the cough syrup, the local health authority raided various pharmacies, while seizing supplies of the syrup, according to BBC News.  The factory manufacturing the syrup was identified and has since been sealed.  So far, three people have been arrested.

Samples of the syrup have been sent off for testing.  According to BBC News, it is possible the people who died might have added an extra ingredient to the syrup, in order to strengthen their high.

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