Bradford scientists have revealed how a 13-year-old Inca ice maiden was drugged with cocaine and alcohol leading up to her ritual sacrifice 500 years ago.

Researchers at the University of Bradford have shed new light on what happened to her after analysing her long tightly-braided hair.

She was found in 1999 near a mountain summit on the Chile border with Argentina, close to Volcan Llullaillaco.

Tests carried out by the team of scientists at the university’s department of archaeological sciences and published online tonight, showed she was given drugs and alcohol in the final months and weeks of her life as part of an Inca capacocha ritual with chewed coca leaves found still in her mouth.

The Llullaillaco Maiden, named after the mountain where she was found, was buried just below the 6,700m summit. Two other younger children, a six-year-old girl and seven-year old boy were also found in separate graves near her.

Lead researcher Dr Andrew Wilson said: “Hair grows around one centimetre a month and, once formed, doesn’t undergo any further alterations.

“Substances such as cocaine and alcohol leave markers which can tell us how much the person was consuming when that section of hair was growing.

“From the Maiden’s hair, we have a two-year timeline running up to her death, showing us some of what she ate and drank.”

The hair showed the teenager had consumed cocaine from eating coca leaves and consumed a concoction of coca and alcohol together – all three of the children had both coca and alcohol in their systems.

The Bradford scientists discovered the maiden’s consumption of coca went up sharply 12 months before her death, and then peaked again six months before she died when she was eating almost three times more. She was also drinking more alcohol in her final weeks.

Dr Wilson has compared the team’s findings with historical accounts produced by the Spanish, dating from the Colonial period, and said: “We think it’s likely the maiden was selected for sacrifice 12 months before her death.

“She was then probably involved in a series of rituals, involving consumption of coca and alcohol, in the build-up to her sacrifice, which kept consumption at a steady level.

“Both substances were controlled, were considered elite products and held ritual significance for the Inca.

“At the altitude the children were found, death by exposure is inevitable. There was no evidence of physical violence to the children, but the coca and alcohol are likely to have hastened their deaths.

“The fact that in her final weeks the maiden shows consistently higher levels of coca and alcohol use compared to the younger children, suggests there was a greater need to sedate her in the final weeks of life.”

The team’s conclusions are confirmed by the position in which the girl was found, seated cross-legged, with her head slumped forward and her arms resting loosely on her lap, her headdress intact and the artefacts around her undisturbed. The researchers believe she was placed in the burial chamber while heavily sedated, her position carefully arranged and the artefacts placed around her.

Children, often as young as four years old, and girls around the age of puberty were donated for sacrifice by their parents and from communities which were under control of the Inca empire.

Although it could have been deemed an honour without need for sadness, it must have created a climate of fear, said Dr Wilson.