The unrest in Leicester, which erupted last weekend, was the culmination of several weeks of growing tension between parts of the Hindu and Muslim communities in the English city, the media reported.
It reportedly began after a cricket match between India and Pakistan, at the end of August, reports the BBC.
Whether the match inflamed existing tensions or served as an opportunity for outside instigators is now the subject of intense speculation.
A total of 47 people have been arrested, 20 over the weekend and some have been sentenced for possession of weapons.
The fight has spilled online as well, says the BBC.
Claims of attacks on people because of their religion have gone viral, though many are unverified and, in one case, confirmed by police not to have happened.
On Wednesday, officers urged people not to share unverified claims on social media.
Leicester Magistrates' Court heard one man sentenced for carrying a knife had been influenced by social media, the BBC reported.
Footage shared by both Hindus and Muslims on social media, allegedly taken during the unrest in the past few weeks, shows groups from both sides, masked men banging on people's windows in Hindu-majority areas and pulling down religious decorations, and others marching down predominantly Muslim-populated streets, chanting 'Jai Shri Ram', the BBC reported.
One video posted online shows a man climbing on to the roof of a Hindu temple, on Belgrave Road, and pulling down a religious flag.
In another video, shared by the temple itself, on its Facebook page, a group of men set one of the temple's flags alight.
According to Leicestershire Police, a significant number of those arrested in the disorder were not from the city.
On Monday, Temporary Chief Constable Rob Nixon said they had seen "a group of people from other cities come to our city to disrupt and cause harm".
Some activists speculate Hindu nationalist groups from India are also involved, BBC reported
Violence between Hindus and Muslims is extremely rare in the UK, especially in Leicester, which is known for its particularly strong sense of cohesion.
There's long been solidarity between Hindus and Muslims in the UK, as two diasporic minority communities that, in Britain, face similar problems of racism and discrimination.
In a joint statement delivered on the steps of Leicester's Jame Masjid mosque, on Tuesday, community leaders from both faith groups stressed this point.
