"It is with the deepest concern for my son's life and safety that I write to you today," she said in her letter in the wake of the arrest of the gang members.
In a separate statement, Varun, 29, said while he was not personally intimidated by such cowardly threats, strong precautions must be taken to defeat the desperate designs of extremist elements.
"The Home Ministry should respond with the urgency and responsibility that behoves those entrusted with the safety of a whole nation," he said, claiming that it was a plot against his life by dangerous underworld criminals.
The Delhi police on Saturday claimed that the gang had come to the capital to allegedly kill Varun's lawyer.
In her letter to the prime minister, Maneka, Varun's mother and BJP MP, said that they should be kept informed of such issues so that "we can protect ourselves".
"I find it bizarre that we have never been informed of any attempts or even been advised on any security precautions. We simply learn of these attempts through the media," Maneka said, adding that she had spoken to the Delhi police commissioner, who had refused to confirm whether Varun was the target. She said a similar conspiracy had been unearthed in April this year.
"There seems to be a systematic campaign afoot to target him culminating in this design to eliminate him," she said. Appreciating the police for arresting the gang, she, however, attacked the Home Ministry, alleging that it had taken these threats 'casually'.
Appealing to all concerned about his safety to join together to strengthen and protect India against anti-national forces, Varun, in his statement, invoked the name of his grandmother Indira Gandhi, who had expressed the hope that her every drop of blood should reinvigorate this nation.
The six persons, who were arrested on Friday from various parts of the city by the Delhi Special Cell, were produced on Saturday before Magistrate Twinkle Wadhwa, who sent them to seven days' police custody.
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