TIRUPUR: Dharapuram Police have registered a case against Tamil Nadu Assembly Opposition Leader Udhayanidhi Stalin for involving a child in an election campaign meeting at Dharapuram, where the Model Code of Conduct is in force for the bypoll.According to a press release issued by Tirupur district police, the incident took place on Saturday near the Periyar statue in Dharapuram town during an election campaign meeting addressed by Udhayanidhi.Police said the Election Commission had clearly instructed political parties and candidates not to involve children in any election-related activities.Police said Udhayanidhi made a child speak at the campaign meeting in a manner that was insulting to Tamil Nadu Chief Minister Vijay and also used the child for election campaigning.Dharapuram Town Police registered a case against Udhayanidhi. Further investigation is under way, police said.