He ranked among the leading Sikh musicians of his day and was invited to perform kirtan from distant parts. In 1937, he led a chorus to the village of AhIa, in Phalia tahsil (subdivision) of Gujarat district (now in Pakistan), where a gurdwara had suffered mob violence in which one of the officiants had lost his life. The Muslims of the area who formed about 80 per cent of the population obstructed the Sikhs entering the village. In the attack they launched, one Bhagat Singh was killed on the spot and several others seriously wounded, among them Bhai Sundar Singh. Bhai Sundar Singh was removed to the civil hospital at Gujrat where he succumbed to his injuries on 17 June 1937. His dead body was brought to Amritsar and cremated on 18 June.
References :
1. Khalsa te Khalsa Advocate. Amritsar, IQJune 1937
2. Khalsa Sevak. Amritsar, 21-23 June 1937