The incident took place at around 3:30 AM at Mobapada village under Talasati taluka of Palghar when some villagers spotted a youth traversing in the night and suspected him to be a thief, they said.
The victim identified as Vishnu Jadhav, aged around 20-22 years, was apprehended by villagers who then started to thrash him badly and even hit him with sharp weapons, leaving the boy severely injured, sub-inspector, Talasari Police Station, K S Patil said.
The body had several wounds, Patil said, adding the body has been sent to hospital for postmortem.
An offence has been registered against unidentified persons under IPC sections 302 (murder), 342 (wrongful confinement), 147 (rioting), 148 (rioting, armed with deadly weapon) and 149 (unlawful assembly).
Other details of the victim are being gathered and no arrest has been made so far, the officer said.