Police on Wednesday took the three killers of gangster-turned-politician Atiq Ahmed and his younger brother Ashraf on four days of remand.

Arguing that they needed time to investigate all aspects of the crime committed in Allahabad on April 15, the police had sought 14 days of custody but the sessions court granted them four days.

Three small-time criminals — Luvlesh Tiwari, Sanny Singh and Arun Maurya — had approached Atiq and Ashraf posing as journalists on Saturday night when the duo were answering reporters' queries while being escorted by the police to a medical college in Allahabad for a check-up.

The trio fired at the brothers from a close range and surrendered on the spot. The motive of the murder is yet to be ascertained.

A police officer in Lucknow said on the condition of anonymity: "We needed more time as we wanted to take the criminals to all those places where we had taken Atiq and Ashraf after they were brought to Allahabad from Sabarmati and Barielly prisons, respectively. We also want to take the killers to their homes in Banda, Hamirpur and Kasganj districts. We need to know who were in touch with the killers in the last one month. The recreation of the crime scene will also take two days.”

“We will apply for further remand after completing the first phase of interrogation," another police officer added.

Lodged in jail in the murder case of former BSP MLA Raju Pal in 2005, the two brothers were brought to Allahabad to be produced in a court for their alleged involvement in the February 24 murder of Umesh Pal, a lawyer and witness in the Raju Pal case.

The killers were produced in the court amid tight security. The police had shifted them from Naini (Allahabad) to Pratapgarh jail on Monday under the apprehension that the gang members of Atiq could try to kill them. Aliq's eldest son, Ali is lodged in Naini jail.

The National Human Rights Commission has served a notice to the Uttar Pradesh police to explain how the duo, one of them a former Samajwadi Party MP, were killed in police custody.

The notice has been served to Uttar Pradesh director-general of police Rajkumar Vishwakarma and Allahabad police commissioner Ramit Sharma, asking them to furnish a detailed report within four weeks.

In its notice, the NHRC has sought a reply on the aspects that led to the deaths (including time, place and reason for arrest/detention), complaint and FIR registered against the deceased, arrest and inspection memo, and seizure and recovery memo. The commission also sought to know whether the information of the arrest of the three assailants was given to their families besides seeking the medical-legal certificate of the deceased, extract of the police general diary, inquest and post-mortem report, recording of the post-mortem of the deceased, site plan of the scene of occurrence, chemical and histopathology examination of viscera, and forensic and magisterial inquiry reports.