A Greek coroner has concluded that a British scientist whose disappearance sparked a huge search on the island of Ikaria was killed when she fell into a deep ravine.

Natalie Christopher, an astrophysicist and keen athlete, was likely to have died instantly, the country’s leading state pathologist said after examining the 35-year-old’s body at the scene of the fall.

“There are many findings … and they are consistent with a fall from a height,” Nikos Karakoukis told the media in the first official assessment of the incident.

The coroner, who flew to Ikaria by helicopter on Thursday, said all evidence, including examination of the site, led him to the conclusion that Christopher had died in an accident.

He said, however, that only an autopsy and toxicological tests would shed full light on the cause of death.

The body of Christopher, who went missing on Monday, was transported to Athens late on Thursday. Forensic scientists are expected to complete a postmortem in the coming days. Until the pathology report was fully concluded, investigations would continue to be part of a criminal inquiry, the Greek police force spokesman Theodoros Chronopoulos insisted. Homicide detectives from the Greek capital also inspected the site.

“We are aware of the coroner’s remarks, but we are still not in a position to entirely rule out everything,” he said. “We are, for example, still examining the possibility of her having been pushed by someone else.”

The ravine was barely a mile away from the hotel where the Anglo-Cypriot, who lived in Cyprus, had been on holiday with her 38-year-old partner. He woke to find she was not in their room and when he called her mobile phone was told she was out jogging. When she failed to return from the run he reported her missing.

Police said that although investigations were ongoing, the partner was not considered a suspect.

Tributes poured in for Christopher, a respected peace activist who dreamed of reuniting Cyprus. President Nicos Anastasiades was among those who expressed sorrow, calling her death “an unjust loss of a young scientist and active citizen who had her whole life ahead of her and much to give”.

The island’s leading bicommunal group, Unite Cyprus Now, described Christopher – who had brought young Greek and Turkish girls together seeking to empower women in both communities through sports – as an inspiration. “Cyprus has lost one of its best,” it said of the Oxford-educated graduate.

More than 40 police officers, escorted by teams specialising in phone tracking technology, firefighters, volunteers and coastguard officials participated in the operation to find Christopher. When, two days later, she had still not been found, police deployed sniffer dogs and dispatched a helicopter equipped with infrared cameras to Ikaria.

Volunteer rescue workers who found her body said part of it had been covered by a large boulder that appeared to have dislodged from the ravine – and which the rock climber may have clung on to as she tried to scale up or down the cliff face. The scientist’s mobile was clearly visible, its screen smashed in the fall.

Vangelis Kriaras, a volunteer, told local TV rescue workers had come close the site “at least twice before” since Christopher went missing, but because of its inaccessibility had failed to spot her. It was only when one volunteer walked through the gorge that her body was discovered.