The Manx constabulary is flagging up concerns of violence as they predict the arrival of UK drug dealers to Manx shores.
The criminals are expected to travel to the island in the coming weeks to collect owed cash.
Border restrictions for the Isle of Man eased on 28 June.
As the borders reopened police increased their patrols and worked in conjunction with the Merseyside force to head off any problems.
Officers are urging anyone with information or any concerns to contact the anonymous Crimestoppers Line on 0800 555 111.
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