The driver whose car rammed into Gopinath Munde's vehicle on Tuesday, killing the Union minister, was arrested but later released on bail by a Delhi court.
Gurvinder Singh, 32, was arrested from the spot, said police.
Singh was driving the Tata Indica car which hit the senior Bharatiya Janata Party leader's Maruti Suzuki on the side he was sitting.
"We are investigating whether he (Gurvinder Singh) jumped the red light in the morning," joint police commissioner MK Meena said.
A resident of Mehrauli area in south Delhi, Singh works as a driver. He was on his way to work when his car hit Munde's vehicle at Aurobindo Chowk in Delhi around 6.20am, sources said.
Ashok Gujjar, a friend of Gurvinder Singh, said: "I was at Janpath when I got to know about the accident, and immediately rushed to a police station. He is not a bad driver and will never jump red lights."
Gujjar said his friend was a seasoned driver and drove cars such as Mercedes and Ford Endeavour.
Police registered a case against the arrested driver of rash and negligent driving, causing death.
According to sources, Singh was also questioned by Intelligence Bureau officials considering the "sensitive nature" of the case. He was later presented in a local court, which granted him bail.
Metropolitan magistrate Puneet Pahwa granted bail to Singh, saying the case falls under a bailable offence and declined the police plea seeking 14 days' judicial custody of the accused.
Police told the court that the Special Cell and Intelligence Bureau (IB) are investigating to find out any possible conspiracy behind the incident and Singh's custody is required.
On this, the court said if any conspiracy is unearthed, the police can seek the custody of the accused then.
The court asked Singh to furnish a personal bond of Rs 30,000 and a surety of like amount.