The incident took place in Bada Jagannathpur last night as unknown gunmen shot foodgrain trader Santosh Kumar Chaudhary, Senior Superintendent of Police Ranjit Kumar Mishra said.
Chaudhary died on the spot and the body has been sent for post-mortem at Sri Krishna Medical College and Hospital (SKMCH).
A probe was on to find out the motive behind the murder of the trader, the SSP said.
Local people blocked Muzaffarpur-Darbhanga Road by burning tyres to protest against the trader's murder as well as that of an engineer hailing from the same area in neighbouring Vaishali district whose body was recovered earlier this morning.