Patna district magistrate Sanjay Kumar Singh and (above) city superintendent of police (central) Shivdeep Lande. Telegraph pictures

Patna, Sept. 14: The mystery person, who called up Patna city superintendent of police (SP) (central) Shivdeep Lande and Patna district magistrate (DM) Sanjay Kumar Singh threatening them with dire consequences, has changed gears.

With Lande returning to duty today after a 10-day leave, the man called up Patna rural superintendent of police Vivek Kumar, the acting city SP during Lande’s absence.

The call came on Lande’s official mobile number on September 3, a day after the officer left for his leave. Today, the caller rang up on the landline number of Gandhi Maidan police station, which falls under Lande’s jurisdiction.

The threat was the same again though this time, the calls originated from a different mobile number.

Amid all the drama, the city police, who claim to crack tough cases, have not been able to make any breakthrough regarding the caller’s identity even after a fortnight.

The police remain clueless about the anonymous caller who threatened the Patna DM on August 30. On August 27, claiming to be a Maoist area commander in Jamui, the caller had threatened to kill Lande on his official mobile number for showing excessive interest in the Kundan Singh case.

Kundan, a dreaded criminal, now lodged in jail, is the primary accused in the murder of transporter Ravikant Choudhary on July 27.

“Earlier, the calls were coming from mobile number 7654738472. There were more calls after the first one and with the caller switching off his phone every time after few seconds. It was difficult to nab him. The person had got the SIM after providing documents belonging to somebody else with a clean background. Before going on leave, I had given the official mobile number to the rural SP and he got a call on September 3 from another mobile number (8804950479),” Lande told The Telegraph. The police again checked the phone records and it was found that the caller had got the number after providing documents of the same person’s family member.

“This time, he got the number against the name of the person’s father. But the photograph is the same. So we know that the caller is the same person,” the officer said.

Moreover, the caller gave quite a few calls on the landline number of Kotwali and Pirbhore police stations. Police sources said they were still to trace the culprit.