The Special Investigation Team (SIT) of city police today took over the probe into the killing of a police constable by three unidentified assailants even as Viqaruddin, said to be a member of the banned SIMI, was emerging as the key suspect.

The case was transferred from Hussaini Alam police station. The incident took place last evening at Shah-Ali Banda area in the old city of Hyderabad, police said.

"The case was today handed over to SIT for a thorough investigation into the death of police constable U Ramesh," a senior police officer told PTI.

Police officials, meanwhile, said some eyewitnesses have identified one of the assailants as Viqaruddin, said to be a member of the banned Students Islamic Movement of India (SIMI), going by his photo.

Viqaruddin, allegedly having links with terror outfits like HUJI, is wanted in connection two attacks on policemen on December 3, 2008 and May 18, 2009.

The body of Ramesh was shifted from Osmania General Hospital (OGS) here to his native Madanapalli in Chittor district late last night after an autopsy.

Three bullets were fired at Ramesh and one bullet was recovered from his chest during autopsy.

It was for the third time in the last 17 months that suspected terrorist elements attacked policemen on duty in Hyderabad city. Two persons were killed and as many injured in these incidents.

Alleged ISI operative Viqaruddin opened fire on the sleuths of counter-intelligence cell at IS Sadan in December 2008 injuring a head constable, according to police. He was also allegedly involved in the shootout at Falaknuma in which a home guard died and a police constable was injured on May 18 last year, the second anniversary of Mecca Masjid blast.

Viqaruddin, against whom the Special Investigation Team of the city police has already registered a case, is a resident of Old Malakpet area here and had joined Darsgah-e-Jihad-o-Shahadat (DJS), a suspected front of SIMI.

Police say he is a strong follower of jihadi ideology and has now emerged as a major challenge for them.

Police Commissioner A K Khan had earlier this month claimed that they had obtained clear leads on Viqaruddin and hoped to nab him soon. The latest incident comes four days ahead of the third anniversary of Mecca Masjid blast in which five persons were killed.