The man, Hilal Ahmed, about 24 years old, was being questioned by intelligence agencies after officials of the customs department found the badge from his luggage during checking at the Integrated Check Post (ICP) in Attari, 30 km from here.
Ahmed, who had gone to Pakistan about 10 days ago through the Attari border, returned on Tuesday.
Security officials said further investigations were in progress.
The Hizbul Mujahideen is the oldest terrorist outfit spreading its separatist agenda in the Jammu and Kashmir state. The outfit operates from Pakistan.
