Gardai yesterday seized over €500,000 worth of drugs at a number of rented houses being used as DIY cannabis factories.
Landlords were warned last night to be vigilant after gardai uncovered the scheme and arrested three Vietnamese nationals who are believed to have been used to house-sit the plants.
An incident room has been set up at Castlerea station. Yesterday, gardai questioned two men, aged 51 and 54, and a 47-year-old woman in Roscommon, Boyle and Longford stations in connection with the raids.
They are all Vietnamese and were detained under section two of the Drug Trafficking Act.
A garda spokesperson said they can be held for up to seven days by which time they will either be released or charged.