New Delhi, May 25 : A team of National Investigation Agency (NIA) is likely to visit Nagpur-based office of Road Transport and Highways Minister Nitin Gadkari in connection with the threat calls made by a murder convict to the minister's office there. However, the probe agency is yet to make an official statement. On May 9, a team of NIA visited Gadkari's Nagpur office. According to sources, one Jayesh Pujari, a murder convict, was behind the threat calls. He was subsequently arrested from Belgavi jail in Karnataka. The Nagpur Police lodged a case under the Unlawful Activities (Prevention) Act (UAPA) against him. Sensing the gravity of the matter, the NIA is also probing it, they added. What is the case: A call was received on the landline number at the official residence of Gadkari in Nagpur around two weeks back. A staff member who answered the call was threatened by the caller who wanted to speak to Gadkari and threaten him. This was not the first time Gadkari's office in Nagpur received a threat call. Earlier in January and March, the minister's Nagpur-based office, had received similar calls. Threat call in Delhi : Gadkari's Delhi office too had received a similar call following which the Delhi Police were informed. The police told IANS that they have initiated a probe. Without divulging more information, police said that the case is under investigation. /IANS