Chennai: The city police arrested four men and secured a juvenile in two separate cases of narcotics possession, following surveillance operations by the Anti-Narcotics Intelligence Unit (ANIU) and the city police teams on Thursday and Friday.In the first incident, Periamet police, in coordination with ANIU, arrested three men and secured a juvenile for possessing heroin. Based on a tip-off about drug movement, police kept vigil along Patnool Sardar Jung Street on Thursday. A group of four was found loitering suspiciously. When questioned, they gave evasive responses, prompting a search that led to the seizure of 14.97 grams of heroin.The arrested were identified as Sharif Mian (23), Mohammed Hussain (36), and Sagar Debnath (24), all hailing from Tripura. The juvenile accomplice was admitted to a govt observation home. The adult suspects were produced before a magistrate and remanded to judicial custody.In a separate incident, Valasaravakkam police arrested a 22-year-old youth involved in methamphetamine peddling. The suspect, J Joy Sujaykumar of Kodaikanal, was under police radar following the arrest of his associate, D Boopalan (21) of Saligramam, in February with four grams of methamphetamine. After sustained efforts, police traced Joy to a hideout on Friday and took him into custody.He was also produced before a magistrate and remanded to judicial custody. Police said investigations are ongoing to trace further links in both drug networks.