Answer
In 1978, Bhindranwale had a clash with the Nirankaris at Amritsar, which resulted in the deaths of 13 Nirankaris. This clash was a result of tensions between the Sikhs and the Nirankaris, which had been growing for some time. The Nirankaris were a sect of Sikhism that was considered to be heretical by some Sikhs, and Bhindranwale had been outspoken in his criticism of them.