Bhubaneswar: The special task force (STF) investigating the mysterious trafficking and abandonment of five infant orangutans in Balasore’s Bichitrapur forest is facing a major hurdle from overlapping mobile networks along the Odisha-West Bengal border, officials said on Friday.Investigators revealed that mobile towers in the border region frequently switch between Odisha and West Bengal networks, creating complications in analysing tower dump data collected from the area. The presence of multiple service providers with overlapping coverage has further increased the challenge of identifying suspicious mobile numbers and tracking the movements of possible suspects.STF sleuths are currently filtering thousands of mobile numbers that were active around the tentative time the endangered apes were abandoned in the forest during the early hours of Sept 8. Officials said the border location has turned electronic surveillance into a herculean task, as a handset located in one state may get connected to a tower in the neighbouring state, creating confusion in location mapping.“Our effort is on to nail the traffickers. There is huge data to be analysed before zooming in on some suspected vehicles so that further move can be made in the investigation. Only when we get some solid clues, our men will proceed to the neighbouring state,” said a senior STF officer associated with the probe.The STF is also examining CCTV footage, vehicle movement records and other digital evidence to establish the route through which the critically endangered primates were transported before being abandoned in Balasore. Investigators believe the traffickers carefully planned the operation to avoid detection.Meanwhile, forest minister Ganesh Ram Singhkhuntia expressed confidence that the investigation would reach its logical conclusion and those involved in the international wildlife smuggling racket would be identified and brought to justice.As the probe intensifies, veterinarians monitoring the rescued orangutans at Nandankanan Zoological Park have reported health concerns. Aditya Acharya, chief coordinator of the Centre for wildlife health at OUAT, said three of the five orangutans have been diagnosed with anaemia, indicating that they were separated from their mothers at a very early age and hand-reared. “Iron supplements have been given to raise their haemoglobin level. It should help improve their condition,” Acharya said.The five rescued orangutans remain under close observation as investigators continue their search for the traffickers behind one of the most unusual wildlife crime cases in recent years.