Yakoob Ali, Ashraful Alam and Zainul Abedinhad been living illegally and worked at a factory here. They were arrested last evening here under Kotwali police station area, inspector Kotwali Anil Misra said.
The trio were trying to acquire passport through fake documents, Misra said, adding that they told police that they had been illegally staying here.
A case has been registered and further investigations were on, he added.