Amravati Police stumbled upon the links between the social media posts supporting Nupur Sharma and the murder of chemist Umesh Kolhe during the investigation and didn't suppress the case as alleged, police commissioner Arti Singh said on Monday.

She also said that police didn't disclose the information earlier given the "very sensitive" nature of the murder case and to avoid any untoward incident.

Addressing a press conference in Amravati, Singh said seven accused, including the mastermind of the June 21 murder, were arrested by the police while the search is on for one more person, identified as Shamim.

On Monday, the NIA has sought the custody of four of the seven accused and filed an application before the local court.

The police commissioner disclosed that three more residents of Amravati were threatened and made to apologise by some people after they extended their support to Sharma on a WhatsApp group.

Only one of the three persons has lodged a complaint and the investigation is underway.

"Some videos have gone viral. We have information that three people had received threats. we are investigating suo motu. We are also investigating these videos and Whatsapp screenshots," she added.

Singh said the investigation into the case will be handed over to the National Investigation Agency by Tuesday morning after completing formalities.

She said she had received the letter to hand over the probe just now.

Kolhe (54) was stabbed in the neck on the night of June 21, which led to his death.

Prima facie, the motive behind the murder was Kolhe's support for Nupur Sharma, the former spokesperson of BJP whose comments on Prophet Mohammad had triggered huge outrage, on social media.

Singh dismissed the allegations levelled by Amravati MP Navneet Rana that the police had tried to suppress the murder case and tried to pass it off as a robbery.

"Initially, we worked on different theories and there was no strong evidence with us to link the murder with the Nupur Sharma case as Kolhe's family members did not tell us that he had received threats on the phone or through WhatsApp and Facebook. It was a blind case for us then," Singh added.

She also said that Amravati police came to know about the Nupur Sharma connection in the Kolhe murder case during the investigation but chose not to make the information public due to the sensitive nature of the case.

Speaking on the investigation so far, the police commissioner said two motorcycles and three knives used in the crime were recovered from the accused.

Singh also said the mastermind of the crime Irfan Khan, who was arrested, had paid Rs 10,000 and a motorcycle to the other five accused.

A court on Sunday remanded Khan in police custody till July 7.

Singh said another accused Yusuf Khan had close relations with Kolhe and the police called him for interrogation after the incident.

On the role of Shamim in the murder, Singh said he rode a motorcycle with another accused sitting pillion.

"As per our information, he (Shamim) had no major role in the incident. He is absconding," Singh added.

Singh said the NIA has requested for the remand of Mudassar Ahmed, Shahrukh Pathan, Abdul Taufik and Shoeb Khan before the court after their police custody expired on Monday. "The NIA on Monday applied for their custody before the court," Singh said.

She said the police are interrogating Dr Yusuf Khan from day one as he and Kolhe had some financial dealings between them. "Since the matter was sensitive we did not want to make any comment in a hurry to avoid any untoward incident," Singh added.

"If we wanted to suppress the case, we wouldn't have arrested the accused persons. We arrested two of them on a day, two more the next day, one each on Friday and Saturday and have identified the eighth accused today," Singh added.

Singh said the police never registered any offence of theft.