The police arrested a CPI(M) worker on Sunday, in connection with the murder of IUML supporter Muhammad Aslam in Nadapuram in Kozhikode district.
Reports say that the police believe Ramesh, a native of Vellur, to be the key suspect in the murder. Ramesh allegedly followed Aslam on the day of the murder and passed on information about him to the gang who killed him.
20-year-old Aslam was murdered on August 12 and had 67 stab wounds on his body.
He was the fourth accused in the murder of a DYFI worker Shibin earlier this year, and was acquitted in the case.
After the police conducted raids at the houses of many CPI(M) leaders, a DYFI worker was arrested for allegedly arranging a car for the assailants.
Another CPI(M) leader K Anil Kumar was on Thursday arrested for arranging accommodation for one of the accused in the case, but was later let out on bail.