One person has been arrested in connection with the fatal stabbing of a teenager in a train in Haryana, police said on Saturday.
Authorities said four more accused had been identified, but refused to disclose their identities.
The CPI-M said on Saturday that such crimes are a result of "toxic campaigns" of the right-wing outfits.
Accused Ramesh, 35, was arrested from his native place Palwal in Haryana late Friday night on the charge of involvement in the murder of 16-year-old Junaid, a senior police officer told IANS.
Ramesh was later sent in three-day police custody by a local court.
"He is claiming he didn't stab Junaid, and also not telling who all were with him during the crime on Thursday night."
The officer said three police teams have been formed to identify and arrest the remaining attackers who were part of the mob that attacked the four youths.
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A Government Railway Police official told IANS that Section 298 of the Indian Penal Code pertaining to utterance of words etc. with deliberate intent to injure religious feelings of any person had been added to the case on Saturday.
Earlier, the GRP registered a case of murder and criminal assault.
On Thursday night, Junaid and his friends Hasib, Shakir, and Mohsin were returning to their village on a Mathura-bound passenger train after shopping at Sadar Bazaar in Delhi.
In his police complaint, Hasib said at least 15-20 persons boarded the train at Okhla railway station and asked them to vacate seats for them.
All four were thrashed all the way from Tughlakabad to the Ballabhgarh railway station and were attacked with sharp-edged weapons and later thrown out of the train at Asaoti railway station in Palwal district.
Media reports earlier said the murderous attack followed rumours about beef eating by the four youths.
Junaid succumbed to his injuries on Thursday night in a hospital. His three friends were injured, two of them critically, and are under treatment at the All India Institute of Medical Sciences Trauma Centre in Delhi.
Earlier in the day, a Communist Party of India-Marxist delegation led by Brinda Karat visited Junaid's native village.
Karat told IANS: "It should not be seen as a routine crime. It is a result of the toxic campaigns of the sangh parivar."
"Public spaces have been communalised -- whether trucks on roads or trains. And if these spaces are being communalised, there are going to be very serious implications."
The CPI-M leader questioned how persons with sharp weapons were allowed to board the train.
The CPI-M delegation said area villagers in Haryana had told them that such incidents of communal and abusive comments on local trains were commonplace but police had not taken any action on complaints in this regard.
--IANS
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