Four persons, including a 50-year-old Delhi government employee, were arrested on Wednesday in connection with the killing of a Muslim youth onboard a Mathura-bound train, the police said.
With these arrests the number of those held in the case related to the stabbing of 17-year-old Junaid has reached five but the "prime accused" was still at large, they said.
The arrests were made six days after the incident, which triggered a nation-wide outrage.
"We have arrested four more persons, including three youths, aged between 24 and 30 years and a 50-year-old man," Kamaldeep Goel, the Superintendent of Police (SP), Government Railway Police (GRP), Faridabad, said.
Goel said the "50-year-old man is a Delhi government employee".
Asked about the post the accused held, Goel said, "I am revealing only the fact that he is a Delhi government employee."
Police claimed that 50-year-old's role was being investigated for allegedly instigating others.
The four arrested accused belong to areas close to Hodal near Palwal in Faridabad and are believed to be regular commuters, police officials said.
Goel said that with these arrests, the sequence of events which led to the stabbing of Junaid has also, to a large extent, become clear.
Junaid was stabbed when he along with his brothers was returning home to Khandawli village in Ballabgarh after shopping for Eid in Delhi on Thursday.
Goel said that it had come to fore that the 50-year-old man had entered into an altercation with Junaid and his brothers over seat sharing.
"He then passed some remarks hurting the victims' religious sentiments. Our investigations show that this 50-year-old man entered into an argument with the victim and his brothers from Okhla over seats.
"However three youths who had boarded the train at New Town Faridabad station also got involved in the quarrel with the 50-year-old man egging them on," Goel said.
Asked if the person who had stabbed Junaid had been nabbed, the SP said the "prime accused" was still at large. He, however, expressed confidence that "now, we have got crucial leads and he too will be in custody soon".
Police officials said that CCTV footage procured from various points close to the incident site was being scanned for more clues to nab the prime accused.
Junaid was stabbed to death while his brothers - Hashim and Sakir - were injured by a mob which also allegedly hurled slurs against them onboard the Delhi-Mathura passenger train between Ballabgarh and Mathura stations on Thursday night.
Junaid's body was dumped close to Asaoti village in Faridabad district.
Police had earlier announced a reward of Rs 1 lakh for credible information leading to arrest of the accused in the case.
One person who had been arrested earlier had been remanded to judicial custody by a court in Faridabad district.
The accused person arrested earlier, while speaking to reporters, had alleged that he was in an inebriated state and had attacked the teenager after being instigated by fellow passengers.