Jagtar Singh Tara was doing time for a massive bombing in 1995 that killed Punjab Chief Minister Beant Singh and 17 others.
Jagtar and two others escaped from Burail Maximum Security Jail after tunnelling 29 metres from their cell and under the prison wall.
Releasing pictures of the wanted man, Gen Jatuporn Klumpasut, International Security Operations Command Region 4, said that he had been told by Indian officials that Jagtar had been sighted in Malaysia and was thought to be trying to make his way to Pakistan, possibly through Thailand.
An arrest warrant has already been issued so that Jagtar can be arrested immediately if he is found in Thailand.