Sabotage as a likely cause of derailment of the New Delhi-Dibrugarh Rajdhani Express near Chhapra in north Bihar, which claimed four lives early Wednesday, was back in circulation on Thursday.
22 persons were also in injured in the mishap when 12 coaches of the Assam-bound train derailed. Five of the derailed coaches had overturned.
The division railway manager (DRM) of the Sonepur division of east central railway (ECR) zone emphatically reiterated on Thursday that he had personally seen "17 Pandrol clips removed" at the mishap site.
"Not only were the clips removed, I saw a crater on the ground at the same spot," said Rajesh Tiwari, the Sonepur DRM, under whose jurisdiction the mishap occurred.
"Prima facie, it appears to be a case of sabotage. But we will know for sure only after the commissioner, railways safety and forensic experts come out with their reports," he added.
Pandrol clips, named after the manufacturing company Pandrol track systems, are used to fasten tracks to sleepers, the rectangular slaps of concrete placed between parallel railway tracks.
According to Pandrol's website, the clips "comprise a few, simple components with elastic fastenings which continue to grip the rail under vibration".
Removal of these elastic rail clips, said a retired railways official, was an almost certain way of causing a train to derail, especially one travelling at high speed.
However, the DRM's claim was contested by Saran superintendent of police Sudhir Kumar Singh, on two counts.
The SP told a section of the media on Thursday that the railways had been alerted in advance about a Maoist bandh and the threat arising from it.
At the same time, he reiterated the Bihar government stand that there was no evidence at hand to suggest Maoist role in the derailment.
"Following an alert from special branch of the Bihar police that Maoists might cause mischief during their bandh, we had alerted the railway authorities. Yet no pilot train was run ahead of Rajdhani," he claimed.
At the same time, the Saran SP also claimed the police had found no evidence of any Pandrol clip being removed or any other evidence of sabotage.
The DRM, however, told a TV channel that he had not received any such letter from the Saran SP.
"Only the government railway police (GRP) had given a memo for a threat on the Hajipur-Muzaffar route (not for the one on which the Rajdhani mishap took place)," he insisted.
Sources said while any Maoist role was a matter of probe, Pandrol clips were also targeted by thieves who stole them to be sold in the scrap market.
Last month, on May 8, about 45 Pandrol clips were found removed from the railway tracks between Kalamna and Itwari stations near Dipty signal in Nagpur (Maharashtra), endangering the lives of many passengers.
On Wednesday, Union home minister Rajnath Singh had said "it was too earlier to blame Maoists" for the mishap.