Khalid, accused of raising anti-national slogans in 2016, was attacked in the heart of the capital outside the Constitution Club, 500 metres away from Parliament, on Monday. He survived the bid on life because of his friends, he said.

After scanning the footage of CCTVs installed near the place where the crime took place, the probe team suspect a man who is seen running away from the location.

"We have scanned over 50 CCTV footages and are trying to identify the suspect," Deputy Commissioner of Police P.S. Kushwah said, adding that the image of the suspect is yet to be shown to the victim and witnesses.

On checking the revolver, the police team found that there were six live cartridges in its magazine, implying that no shot was fired.

However, according to witnesses, the sound of a gunshot was heard, raising questions about the presence of another weapon or another attacker but the police felt it was "premature" to come down to this conclusion.

"We have just taken over the case from New Delhi district police and it would be premature to make such speculation," he said.

Earlier, the police officer said: "We have recorded Umar Khalid's statement afresh and are trying to know about the people that had threatened him earlier too. We have got some good leads."

"The statements of eyewitness have also been recorded by the team to know the sequence of incident," the officer said.

In the FIR, Khalid said that the attacker came from behind and hit his head.

When Khalid turned back, he dragged him and whipped out a revolver aiming to shoot. Khalid's friend Saddak Hussain in the meantime tried to overpower the accused.

"The accused managed to escape and we heard the shot. We informed the local police and later found a revolver lying on a road near NITI Aayog," Khalid said in the FIR.

Khalid had gone to the Constitution Club to attend a "United Against Hate" programme where the listed speakers included noted lawyer Prashant Bhushan, MP Manoj Jha and journalist Amit Sen Gupta.