Amit Kumar Singh, who was arrested on Tuesday on charges of killing a person by throwing him from the eighth floor flat of a judge in Patna last month, had threatened to blow up the Prime Minister's Office (PMO) and Tihar jail in New Delhi, police said.
"Last year he (Singh) had made frantic calls to the Sarojini Nagar police station in south Delhi threatening to blow up the Prime Minister's Office and Delhi's high security Tihar jail, but he could not be arrested then," Deputy Commissioner of Police (Crime Branch) AS Cheema said.
Singh, who is facing 22 cases of rape, murder, robbery, immoral trafficking and theft of laptops and mobile phones, was also wanted in an extortion case, where he had extorted money from a city-based businessman by impersonating as an officer of Central Bureau of Investigation (CBI), Cheema said.
"He told his victim that he was a senior official with the CBI and would book him in false cases."
Singh was arrested on Tuesday afternoon from Majnu Ka Tila area in north Delhi for allegedly killing Suresh Mahto, 30, with his accomplice Pawan by throwing him from the apartment of Sadhna Srivastava, a judge of the Central Administrative Tribunal (CAT), on May 20, in Patna.
According to police, the duo barged into Srivastava's residence to rob her and threw Mahto from the balcony of the 8th floor residence when he resisted them.
While Singh managed to escape after the crime, Pawan was arrested after he jumped from the second floor of the building and suffered serious injuries, police said.
Singh then came to the national capital where he managed to evade arrest on several occasions. "He is very clever, as he never used the same mobile number twice. He could only be arrested after a continuous surveillance for the last 10 days," Cheema said.
Patna Senior Superintendent of Police Kundan Krishna had said that the duo had barged into the judge's flat and tried to take photographs of Srivastava and Mahto to blackmail them on behalf of a former director general of police, who was facing trial at Srivastava's court in corruption cases.