According to reports, the couple was travelling in the bus from Bahraich to Lucknow on Wednesday night when the passenger Raju Misra, 37, suffered a heart attack near Barabanki and died before he could get any medical help.
The bus was about 25 km from Lucknow when the incident took place.
Murli Misra, the elder brother of the deceased, told the media that the bus conductor Mohd Salman and driver Junaid Ahmad forced his sister-in-law to de-board with her husband's body. They also snatched the bus tickets from her, he added.
However, denying the allegations, the conductor said the passenger complained of chest pain after Jarwal road.
He told the couple that a doctor was also travelling in the bus but as he (doctor) could not help much, he decided to take Raju to a nearby private doctor in Ram Nagar.
Mohd Salman said he stopped the bus at Ram Nagar and called doctor D.P. Singh, whose clinic was nearby, to examine the patient, adding that Raju was declared dead in the bus itself.
The conductor said he also called the Dial 100 service of the UP Police but was unable to get any response and so he called the SO of Ram Nagar and asked him to take the body to a Barabanki hospital.
The conductor further said that he called other relatives of the deceased and on the insistence of the woman's relatives, he let her de-board the bus.
Ram Nagar SO Shyam Narain Pandey said the bus conductor informed him that the woman wanted to get off the bus with her husband in Ram Nagar but he asked the conductor to take him to nearest hospital in Barabanki for further medico-legal procedure like death certificate etc.
The SO said he also sent some policemen to the spot but the woman had de-boarded with her husband's body. Pandey said he then arranged a vehicle to take the body to a Barabanki hospital.
The post-mortem was conducted at Barabanki hospital on Thursday.
Assistant Roadways Manager (ARM), Bahraich bus station, Mohd Irfan said he came to know about the incident through social media. He said that an inquiry will be held in the matter.
The matter came to light when Kiran Deep, a twitterati, informed Chief Minister Yogi Adityanath about the incident on his Twitter handle.
( With inputs from IANS )