Celebrations to commemorate the completion of first year of NDA government would commence from the native village of Jan Sangh leader Deen Dayal Upadhyay in Mathura today with a public rally of Modi. This is the first of BJP's 200 rallies to mark its government's one year in power.

The PM will address the rally at village Nagla Chandrabhan, which is Upadhyay's birth place. Through his 'Jan Kalyan' rally, he is likely to address some of the problems and assuage concerns of people living in the village.

Tight security measures have been put in place for the Modi's visit to the district. The village has turned into a fortress, has heliports for three choppers and over 3000 policemen and commandos have been deployed for security.

Ahead of the rally in Mathura today, security agencies and district administration went into a tizzy after a message threatening to kill Modi reached the police and media.

The Uttar Pradesh police has identified the sender of the WhatsApp message and taken his brother into custody. Several people, including SSP Rakesh Singh and some media personnel, had received the message on May 20, following which the mobile number through which the threat message was sent was put under surveillance, police officials said.

SSP Singh said the sender has been identified as Ramvir, a resident of Navli village, and a team under superintendent of police (city) has been constituted to nab him.

"Ramvir's brother Laxman Singh has been taken into custody and is being interrogated. Ramvir had sent the message to some people including media persons," he said.

District Magistrate Rajesh Kumar said Ramvir has sent similar kind of messages on previous occasions as well to scare people. "Ramvir had bought the SIM card under a fake name. A case under relevant sections of the IPC will be registered against him," he said.