The Indian national, 36, using a fake Nepalese passport, was arrested during a sting operation in southern Malaysia on October 24 for immigration offences and deported on Wednesday, Inspector-General of Police Khalid Abu Bakar said in a statement.
The operation conducted by the Counter Terrorism Department on October 24 had uncovered the wanted man hiding in a neighbourhood in the town.
"We believe he was involved in the murder of Rashtariya Sikh Sangat's president Rulda Singh in July 2009. The group was also responsible for several bomb attacks there in April 2010," he said.
Rashtariya Sikh Sangat was an independent socio-cultural organisation that aimed to promote Sikh-Hindu relations. Khalid said the terrorist had fled the country and hid in other countries including Nepal and Thailand before entering Malaysia in 2010.
The suspect was arrested under Section 6(1) of the Immigration Act 1959/63 for entering into the country without a valid travel document. He was the sixth Sikh militant the department had arrested since 2009, Rakyat Post, an online news portal said.