Five men who have been working in the UK illegally were arrested in Oakham and Edith Weston in Home Office Immigration Enforcement raids at the weekend.
Four of the arrests were made at two branches of the L’Oliveto restaurant.
Officers visited the Church Street branch on Friday night, where checks revealed that three members of staff were immigration offenders from Tunisia. Two of the men, aged 35 and 22, had overstayed their visas while one, aged 36, had entered the UK illegally.
Officers also visited the Normanton Road, Edith Weston, branch of the restaurant on Sunday where a fourth Tunisian man was arrested. The 27-year-old had overstayed his visa.
All four offenders have been detained until their removal from the UK.
The owners of the L’Oliveto restaurants now face a potential penalty of up to £40,000 to £10,000 for each of the illegal workers - unless they can demonstrate that appropriate pre-employment checks were carried out, such as seeing a passport or Home Office document.
Also on Sunday, officers visited the West End Convenience Store in Cold Overton Road where checks found a 27-year-old Indian man working at the store had entered the UK illegally.
He has been released on bail while work to remove him from the UK is carried out.
West End Convenience Store also faces a potential fine of up to £10,000 for employing the illegal worker.