Mr Arunja Miguel Benjamin, 31, opened his home to his then-colleague who had financial problems and no place to stay.
But one year later, on June 1, the man moved out as Mr Benjamin was unhappy with the man's behaviour.
Then last Monday, he found his front door splashed with green paint and ‘O$P$’ scrawled on the wall of the lift landing near his flat.
He went to the man's room and found ATM transaction slips and notebooks with records of ATM transfers in the man's room.
He now believes his ex-colleague was involved with loan sharks.