Stating that his family was ready for the test, Prakash said that Rathore should be hanged if he fails in the test.
"We are ready. In fact, we are ready for any test. If we are found lying, police are free to hang us. If Rathore is found guilty, he should be immediately hanged," an upset Parkash said in a news agency report.
Prakash said that Rathore was asking for the test so that he can delay legal action against him.
"Rathore and his wife are making a fool of the police machinery and judiciary. By making such frivolous demands, they are just buying time," he said.
Echoing Prakash's statement, Ruchika's father SC Girhotra said that the demand for narco-analysis test was made to evade arrest.
"The CBI has all the proof against him. There is no need for any other test," he said.
Earlier, Rathore in his statement to the Harayana government has said that he would undergo narco-analysis test only if Ruchika's family and the complainant Anand Prakash's family was willing to undergo the test.
Rathore has been served a notice by the CBI special court, to explain why he should continue getting his pension and why he should not be stripped off his medals.
The former DGP has been convicted for molesting 15-year-old budding tennis player Ruchika Girhotra, who later committed suicide in 1993.
He was sentenced to six months rigorous imprisonment and was imposed a fine of Rs.1,000, but was immediately released on bail.