In a letter to the Prime Minister, the apex religious body of the Sikhs asked him to take up the issue with foreign countries to prevent recurrence of such incidents.
The Centre should strongly take up the matter with US government in the larger interest of Sikhs living in the country, SGPC president Avtar Singh Makkar said.
56-year-old Dalbir Singh was gunned down by unidentified men at a grocery store in Milwaukee city in Wisconsin on Wednesday night.
On August 5, six Sikhs were killed in an attack on a Gurudwara during Sunday morning prayers in Wisconsin.
Dalbir was a regular visitor to the Gurudwara at Oak Creek in Wisconsin but was not present when the tragic incident happened on August five.