Ishmeet, 19, who won the "Voice of India" reality TV show featuring a singing contest in November last year, died July 29 by drowning in the swimming pool of a resort in the Maldives where he had gone to attend an event.
In a letter to the prime minister, Badal mentioned media reports that raised suspicions about the cause of Ishmeet's death.
Badal said the family and scores of admirers of the singer had requested him to seek a probe when he went to attend the memory service of Ishmeet in Ludhiana Sunday. He said that they suspected foul play in his death due to professional rivalry.
The chief minister urged the prime minister to ask an appropriate investigating agency to probe Ishmeet's death.