Borge, who was a technician with Airworks, the company which maintains Ambani's helicopter, was found dead on railway tracks between Vile Parle and Andheri stations last evening.
"The state government must seek a CBI probe into the matter as the entire episode of Bharat's death is not clear. He was in the Army for 20 years and he was strong; he never got depressed. We don't believe it is a suicide," Borge's cousin Sambhaji Botre said.
"Borge's wife and two children are in a state of shock and cannot believe that Bharat has committed suicide," Botre told PTI by phone from Satara, the native place of the deceased in Western Maharashtra where his body has been taken for last rites.
"We knew Ambani's chopper sabotage case was a big issue. In fact Bharat was the one who first brought this to police's notice and helped them in all possible manner," Botre said.
Police say Borge was run over by a suburban train but preliminary post-mortem report has revealed that Borge died due to multiple fractures and injuries, police said.