The activists of the right-wing group claimed that they had gathered there to oppose a court marriage on the basis of 'forged papers', showing the girl as a Muslim.
Soon after the incident, the commissioner formed four teams and nabbed four persons by evening on Friday.
A group of Bajrang Dal men allegedly attacked and stabbed a man, who was travelling to Bengaluru in a private bus along with his female friend, near Pumpwell here on Thursday night.
Two nuns and two postulants were taken off an express train and detained for questioning by railway police in Jhansi on March 19 after complaint from local Bajrang Dal activists.
Vijayan's reaction comes a day after the Union Minister had rejected the charge that the nuns and two others were 'attacked' in Jhansi by some Bajrang Dal activists.
Jhansi nun attack will tarnish image of religious tolerance: Kerala CM Pinarayi Vijayan to Amit Shah
Pinarayi sought strict action against those who had harassed the nuns at Jhansi during a train journey in Uttar Pradesh.
Kerala BJP general secretary George Kurian, who is also ex-vice-chairperson of the National Commission for Minorities described the ordeal of the nuns in detail but he did not name Bajrang Dal.
Officials in Jhansi said the nuns were detained after local Bajrang Dal activists complained that two of the women were allegedly being taken forcibly for religious conversion.
The postulants, who had joined the Sacred Hearts Congregation of the Delhi Province recently, were travelling for the first time to their homes.
On being alerted, police reached the spot and brought the situation under control, an official said.
The incident led to a public protest in the area, prompting the activists to lodge a complaint with Badachana police on Tuesday.
Bajrang Dal leader Rakesh Bajrangi claimed 99 per cent grenade attacks in Kashmir have been carried out by those wearing pheran.
Delhi Police denied any communal angle to the murder and said the fight at the birthday party took place over a business rivalry.
The statement from police came after some outfits, including the Vishwa Hindu Parishad, gave communal colour to the incident.
The victim, a active member of the Bajrang Dal organisation, lived in Mangolpuri and was working as a technician in the Action Balaji Hospital.