Four people have been arrested while about a dozen others detained for questioning in connection with Bajrang Dal activist Harsha's murder in the district, as stray incidents of arson and violence were reported in Tunganagar here on Tuesday morning, police said.

The arrested have been identified as Kashif, Nadim, Asif and Rihan, all in their twenties, police sources said.

"Their background and all other details are being checked", they added.

Harsha was stabbed to death on Sunday night at Bharathi Nagar in the city allegedly by a group of men, who came in a car. Police suspect the involvement of seven people in the murder.

Additional Director General of Police C Pratap Reddy, who is camping in the town told reporters that all the accused have been identified.

"All the accused have been identified by police and arrests have been made. Other arrests would soon be made," Reddy said.

According to him, a few vehicles were burnt in Tunganagar on Tuesday morning, despite prohibitory orders which have been clamped under section 144 of the CrPC.

"Following the murder of Harsha, there was a very tense situation in the city and certain surrounding areas. Additional forces were rushed to Shivamogga and lot of arrangements were made by the deputy commissioner and the superintendent of police to ensure that the fallout of the murder does not spread further," Reddy said.

The official said 14 different incidents of arson and violence took place in the city (after the murder), which would require filing of FIRs.

In three cases FIRs have been registered, he said adding, the police were trying to trace those who lost their motorbikes and properties in the arson and violence.

In Bengaluru, Karnataka Home Minister Araga Gnanendra said over 12 persons have been detained in connection with Harsha's killing and interrogation is on. "The investigation is going on encompassing all the dimensions," he told reporters.

State Revenue Minister R Ashoka said the murder has a link with the ongoing Hijab row in the state.

"This murder happened when the Hijab controversy started. It is evident that there is a link between this murder and the Hijab row," Ashoka said.

A few Muslim girls from Udupi have approached the Karnataka High Court when they were allegedly denied entry to the classes with their Hijabs or the Islamic headscarves on.

In reaction to the girls wearing Hijab, Hindu students started coming to college wearing saffron scarves. The trend of Hijab versus saffron scarves gradually spread to other parts of the state leading to communal tension in some educational institutions.