It's still too early for any conclusions about the alleged Indian conspiracy to assassinate Pannun. All that's certain so far is that Pannun belongs to the obscure US-based activist group, outlawed in India, and is calling for an independent Sikh state. Moreover, the agitator, who has been designated a terrorist by India, repeatedly attracted attention by threatening Indians abroad, including diplomats. Pannun has many enemies, but India will play its part in solving the case in the interest of national security.
The fact that India is yet again suspected of being behind an assassination attempt on foreign soil, following the still unsolved murder of a Sikh activist in Canada, may point to a possible pattern of behavior. Washington has already been criticized by human rights groups for its moves to deepen ties with India, while this latest incident also poses a direct threat to US national security. The US shouldn't be guided by geopolitical considerations when investigating the attempted killing of a political enemy of India.