Police in Madagascar are investigating whether a British student who died after falling from a light plane deliberately opened the doors after suffering a severe reaction to medication.

Alana Cutland, 19, who has been described by her family as a “bright, independent young woman”, fell from the two-door Cessna C168 on 25 July. She had been carrying out research in the remote area of Anjajavy on the island off Africa’s east coast.

Local police say she fell despite the desperate efforts of the only other passenger and the pilot to keep her inside the plane.

The body of the student, from Milton Keynes, who was studying natural sciences at Cambridge University, has not yet been recovered.

Her uncle said she had become sick during her time in Madagascar, possibly due to prescription medicine. Police are investigating her possible use of an anti-malaria drug, reports have claimed.

“She had taken ill after being there for a few days and when she spoke to her mother on the phone two days before the accident she was mumbling and sounded pretty incoherent,” Lester Riley, her mother’s brother, told Mail Online.

“We think she had suffered a severe reaction to some drugs but not the anti-malaria ones because she had taken those on her trip last year to China without any side-effects.”

He added: “What happened, the family believe, was a tragic accident, not a suicide, and we are utterly heartbroken. She was hallucinating, she was unwell, something had made her ill, it must have been a reaction to medication.”

The second-year student had reportedly suffered “paranoia attacks” while on the research trip, during which she was seeking to discover more about a rare species of crab. She had been in regular contact with her mother, Alison, who works at Cranfield University near Milton Keynes, and her father Neil, an environmental engineer, who had reportedly encouraged her to cut short her six-week trip and come home.

Police photographs recreating the incident appear to show the pilot and the second passenger, Ruth Johnson, 51, a friend of Cutland’s, grasping hold of the student’s leg. She is reported to have fallen to her death after a tense struggle to free herself.

The plane’s pilot, Mahefa Tahina Rantoanina, said Cutland had a headache when she boarded and stayed silent during the flight, which was said to be taking her to a hospital so she could be declared fit to fly back to the UK.

“But for the whole time Alana did not say a word – she just struggled with us,” Rantoanina told the Sun. “I have no idea why she opened the door but she did. She opened the door and she jumped. The door did not open itself.”

Local police chief Sinola Nomenjahary said: “The Cessna C168 aircraft was taking off from Anjajavy with three people aboard, including Johnson, Alana and the pilot. After 10 minutes of flight, Alana undid her seatbelt and unlocked the right door of the plane and tried to get out.

“Ms Johnson fought for five minutes trying to hold her, but when she was exhausted and out of breath she let go. Alana then intentionally fell from an aircraft at 1,130 metres above sea level.”

In a statement released through the Foreign Office, her family paid tribute to Cutland, saying she “grasped every opportunity that was offered to her with enthusiasm and a sense of adventure”.

It added: “We are heartbroken at the loss of our wonderful, beautiful daughter, who lit up every room she walk into, and made people smile just by being there.”

Some antimalarial drugs have been associated with potentially severe psychological side-effects in some users, although her family appear to suggest any reaction may have been linked to a different prescription medicine.