The Fishing Harbour police on Tuesday detained four persons suspecting their involvement in the murder of a 34-year-old fisherman, whose body was found near the harbour late on Monday.
Fishermen noticed the body lying on the sands near the harbour and alerted the police.
The police personnel reached the spot and began investigation.
They identified the deceased as Sudarmani, a fisherman from Thangal, Tiruvottiyur.
The body, which showed signs of injury, was sent to the Government Stanley Hospital for post-mortem examination. After scrutiny of CCTV camera footage, the police picked up four suspects from a nearby fishing hamlet.
Initial investigation revealed that the deceased and the suspects had past disputes over petty issues.
However, a senior officer said the interrogation was still under way.