A team of plain-clothes police personnel entered Jadavpur University on Monday after professor Om Prakash Mishra had to walk to his office with folded hands through rows of protesters blocking his way and asking why he was there.

The police said their entry was based on Special Branch intelligence that warned of attempts to create “chaos” after the international relations professor resumed work on Monday.

Left supporters had earlier put up posters calling for a “boycott” of Mishra. On Monday, some of them branded him a “molester”.

The presence of the police on campus spurred speculation on who called them.

Traditionally, the police do not enter a university campus except upon a request from the vice-chancellor or in an emergency.

Many felt that some of the recent Calcutta High Court observations gave the police the liberty to act on intelligence from the campus and move in.

Last week, Calcutta High Court had pulled up the city police for an intelligence failure in apprehending trouble on the campus and the consequent attack on the education minister Bratya Basu on March 1 when a group of students heckled him and physically tried to stop his car from leaving.

Mishra entered the campus around 12.05pm on Monday.

As he tried to walk to his department, SFI supporters, men and women, blocked his way. Mishra hurtled forward with folded hands, and the students followed him. “Please let me go to my office.... This is my department,” he said several times.

Once he entered his office, the students squatted outside in large numbers.

That is when the police first appeared. Around 12.45pm.

Two officers — a man and a woman — went into Mishra’s office. They had Kolkata Police identity cards around their necks.

A few minutes later, the male officer left, and a larger group of plain-clothes personnel moved in. Many in this group were women and did not have the identity cards around their necks. They stationed themselves outside Mishra’s office.

The students kept accusing the professor of pushing them and trampling on their feet.

A few teachers asked Mishra if he had called the police. “I have not called anyone,” Mishra responded before television cameras to try and clear the air.

“There were teachers in my room. Many women students were agitating outside. I saw a few women outside my room. Much later, I realised that they were attached to the police,” Mishra said.

He added: “I had informed the university authorities (about the agitation outside his office), I informed the vice-chancellor. I have no authority to inform the police.”

JU’s VC and other officials could not be reached for comment. Most of them were in a meeting on the campus till late on Monday.

In the afternoon, some of the students started questioning the police and sought the order based on which they entered the university. They said they would not allow the police to leave the campus unless they showed the order.

The officers tried to reason with the students and then moved outside the Arts Building.

By the time Mishra left around 4.50pm, the number of protesters had thinned.

A member of the SFI state committee who looks after the unit in JU, Subhodeep Bandyopadhyay, said: “Some students agitated against Om Prakash Mishra as he had assaulted students on March 1.”

Senior Kolkata Police officers said there was no bar on the police entering an education institution’s campus.

“It is our duty to maintain law and order. The campus is no exception,” a top officer said.

The campus unrest started on March 1 when the education minister went to JU to attend the annual general meeting of a pro-Trinamool Congress teachers’ organisation, of which Mishra is a leader.

A group of students, supporters of Left and ultra-Left students’ organisations, barricaded Basu’s car and one of them, Indranuj Roy, suffered injuries after allegedly being hit by the minister’s car, which he was trying to stop.

Following the unrest on March 1, the bench of Justice Tirthankar Ghosh of the high court criticised the police for an alleged intelligence failure.