A Railway Protection Force (RPF) constable on Monday morning shot dead four people, including a senior colleague and at least two Muslim passengers, on board the moving Jaipur-Mumbai Central Express near Palghar railway station in Maharashtra, officials said.

By the evening, the cold-blooded murders took on an unparalleled turn when a video clip emerged. The clip featuring the purported graphic scenes inside the train compartment shows a person in uniform, whose face is mostly not visible because his back is turned towards the camera, saying in Hindi: “If you want to vote, if you want to live in Hindustan, then I am saying, Modi and Yogi, they are the two, and your Thackeray.”

Three of the victims have been identified as Tika Ram Meena, RPF assistant sub-inspector; Abdul Kadarbhai Mohammed Hussain Bhanpurwala (48), a resident of Nalasopara in Palghar (around 100km from Mumbai); and Asgar Abbas Sheikh (48), a resident of Madhubani in Bihar. The fourth victim had not been identified till late on Monday.

Constable Chetan Singh (34), the murder suspect who hails from Hathras in Uttar Pradesh, was caught with his weapon while he was trying to flee after passengers pulled the chain of the train which stopped near Mira Road station (on the Mumbai suburban network) around 6am.

The murders were carried out in different coaches of the train, suggesting the killer picked out his victims from among the passengers.

The video shows the person in uniform standing near a body lying in a pool of blood and addressing other passengers who have gathered near the door. Some passengers can be seen seated behind him also.

The uniformed person tells the passengers: “They are operating from Pakistan. Your media, this country’s media is showing the news, they are getting to know everything, these people’s masters are there. If you want to vote, if you want to live in Hindustan, then I am saying, Modi and Yogi, they are the two, and your Thackeray.”

Asked about the video, Government Railway Police (GRP) commissioner Ravindra Shisve told reporters: “It is too early to jump to any conclusion, and at this stage, it will be premature to say anything and share any details about the probe.”

“This is the first-of-its-kind of incident on a running train. Passengers are scared. We want to assure them that police will investigate the incident in detail,” he added.

Shisve said the exact reason behind the incident was not known yet. The GRP has formed a special investigation team to probe the murders.

Earlier in the day, the GRP control room and a senior official had identified the accused as Chetan Kumar Chaudhary. In the afternoon, GRP commissioner Shisve told reporters the constable has been identified as Chetan Singh.

Some media reports suggested that the police are investigating if the constable has any mental ailment. But Bhagwan Singh Chaudhary, who identified himself as an uncle of the RPF constable, said in their native village Mitai in Uttar Pradesh’s Hathras that “Chetan never showed any sign of mental imbalance".

Bhagwan Singh told local reporters that Chetan had got the job in 2009 in place of his father, who was also a constable in RPF and had died on duty.

Pravin Chandra Sinha, principal chief security commissioner, Western Railway, told reporters: “He (Chetan) was not upset. He was a bit unwell... later he lost his cool.”

Asked whether Chetan had any mental health issues, Sinha said: “He had a short fuse and lost his temper, leading to the incident.”

Chetan was staying in the barracks. His family includes his wife and two children aged 6 and 8.

Congress leader Jairam Ramesh tweeted on Monday evening: “The cold-blooded murders carried out by an RPF constable is the result of a hyper-charged and highly polarised news media and social media atmosphere. The genie of hate is now out of the bottle and it will take a lot of collective effort to put it back in.”

Ramesh added: “The message of the Bharat Jodo Yatra was aimed to dial down the hate and violence spreading due to the ideology of the RSS, and the politics of prejudice and polarisation of the BJP. Its top leadership is complicit in damaging the social fabric of India. The vast majority of Indians will soon reject this politics of hatred and vengeance.”

Chetan shot dead RPF assistant sub-inspector Meena and another passenger in the B5 coach with his automatic weapon after 5am. He then shot dead another passenger in the pantry car five coaches away and went on to kill one more passenger in S6 coach, which is the eighth bogie from the B5 coach, an official said.

A compartment in the Jaipur-Mumbai Superfast Express in which some of the murders took place near the Palghar railway station, around 100km from Mumbai. PTI picture

A 25-year-old RPF constable, who is the complainant in the case, said that Chetan tried to strangulate him before going on the firing spree, a GRP official said. The GRP official, citing the FIR, said complainant constable Amay Ghanshyaam Acharya said Chetan was not feeling well.

So, ASI Meena advised him to take rest and have medicines when the train arrives in Mumbai. The complainant said Chetan went to sleep but after 15 minutes, he woke up and started demanding his rifle. When Acharya refused to give him the weapon, he tried to strangulate him and managed to take the rifle and left the spot in anger, he said.

Acharya went to the pantry car and narrated the incident to his seniors. Acharya feared Chetan may attack him and so he hid in a sleeper coach.

The assailant later got down from the train and started walking on the tracks between the Meera Road and Dahisar stations. Acharya asked passengers to close the windows and saw Chetan firing on the train indiscriminately, said the official, quoting from the FIR.

According to an official, the alarm chain in the train was pulled around 5.59am. As the train came to a halt near Mira Road station, Singh jumped down on the railway tracks with his weapon and started running. He was nabbed by personnel of GRP and RPF after a chase and his weapon was seized.

“The incident occurred after 5am after the Mumbai-bound Jaipur Superfast Express crossed Vapi station (in Gujarat). RPF constable Chetan Singh, who was on escort duty, opened fire at his senior Tika Ram Meena and went on shooting dead three more passengers in different bogies of the train,” Shisve said.

According to the GRP, Singh fired 12 rounds from his automatic weapon. The GRP recovered eight bullets from his automatic weapon after the incident.

Four RPF personnel, including Chetan, were escorting the Jaipur-Mumbai Central Express from Surat station in Gujarat on Monday.

The accused constable was attached to the Lower Parel RPF post here, while ASI Tika Ram Meena was attached to the Dadar RPF post.

An official said ASI Meena hailed from Sawai Madhopur in Rajasthan. He was supposed to retire in 2025. Meena is survived by his wife, a 20-year-old son and a 22-year-old daughter.