India's railway ministry has recommended that the country's top detective agency should investigate the deadly crash that killed 275 people.
Railway Minister Ashwini Vaishnaw announced the decision but did not give more details.
Railways-led investigations have already started and preliminary reports say a signal fault led to the crash.
The three-train collision on Friday night has been described as India's worst rail accident this century.
More than 1,000 suffered injuries and were taken to hospitals. Some families are still searching for their loved ones.
It's not clear why the Railway Board, the ministry's top decision making body, has recommended a separate investigation by the Central Bureau of Investigation (CBI) when other inquiries have already started.
The CBI investigates high profile criminal causes, including serious financial frauds and murders.
Mr Vaishnaw said on Sunday that "the root cause" of the accident and people responsible for the "criminal act" had been identified.
He added that a "change in electronic interlocking" was the likely cause of the accident. The minister urged people to wait for the final report.
A report by the Commissioner of Railway Safety would be made public soon and it would reveal the cause, he said.
Meanwhile, the railways said on Sunday that the Coromandel Express's engine and coaches crashed into a goods train due to a signal fault and a "change in electronic interlocking".
In railway signalling the electronic interlocking system sets routes for each train in a set area, ensuring the safe movement of trains along the track.
The impact of the crash threw coaches of the Coromandel Express onto a third track and they rammed into the rear carriages of the Bengaluru-Howrah Superfast Express that was coming down the line at a high speed.
More than 3,000 passengers are thought to have been on board the two passenger trains.
Atul Karwal, chief of the National Disaster Response Force (NDRF), said the force of the collision left several coaches crushed. Rescuers had to cut through the wreckage to reach the passengers.
Hundreds of ambulances, doctors, nurses and rescue personnel were sent to the scene and worked for 18 hours to rescue passengers and pull out bodies.
'I pray that we find him': Desperate hunt for the missing
On Sunday night, Mr Vaishnaw said train movement had been restored on the railway tracks where the accident took place.
Reports say several passengers are still missing.
Opposition leaders have called on Mr Vaishnaw to take responsibility for the tragedy and resign.
The ruling Bharatiya Janata Party has responded by asking them not to politicise the accident.
BDST: 1326 HRS, JUN 05, 2023