Hair sample evidence
Dr Piper said: “With hair samples, Zopiclone takes four weeks to show. If ingested orally a drug is normally detected in the blood, then the liver, then the urine sample.
“If someone ingests Zopiclone, it will not be detectable in the majority of the population after a very short period of time - within the blood you’re normally talking within a number of days.
“However with the hair, the drug becomes embedded into the hair shaft. Every human head hair has a bulb with it’s own blood supply, and then the hair shaft. As the hair grows from the bulb any drugs in the body will be passing through the blood and will be incorporated into that hair shaft in small quantities. “That drug will stay in the hair shaft until it is cut off.”
Dr Piper said: “The body samples [from Helen’s body] were all analysed for drugs, each of them analysed for cannabis, cocaine, amphetamine - no drugs of this nature were found in these sample types.
“Each of these body samples were also analysed for prescription drugs - and Zopiclone was detected.
“In addition the chest cavity fluid was found to contain paracetamol. The level of this was low and negligible really - below the concentration you’d expect to have a therapeutic effect.
“With the zopiclone, it was barely detected in the muscle tissue sample [from Helen’s body] - it was a very low concentration. “The liver specimen detected a concentration found to be below a toxic level, to the point where it starts to have a negative effect on the body.”
Hair sample shows drug ingested on more than one occasion'
“Drug finds in hair have to be interpreted very carefully. What we can say is that if a drug is found over a given concentration, that it’s indicative or more than a single ingestion event, and that is what we have in this particular case.” The hair specimen was 35cm in length and analysed in four segments. This allowed us to concentrate on a timescale of early January 2016 through to early March 2016. “We have a three month time period here, so we can see if a drug has been administered over multiple occasions and what sort of time period. “The segment closest to the scalp had a significant concentration of Zopiclone present - as you move further away from the scalp the levels drop, but the drug was detected in all four segments of hair.”
Zopiclone ingested more than once during three-month period'
“There was a very small quantity of the drug in the scalp segment, but this was above the quantity of being a single one off event [of the drug being ingested].
“This piece of hair gives an indication that zopiclone has been ingested more than once during this three month time period.
“The findings would suggest that zopiclone has been ingested in more than one occasion, due to the concentration of the drug we detected.
“I cannot state or suggest quantities taken or dates taken other than this approximate [three month] time period.”
Cannot confirm whether drug was taken by Helen knowingly or not'
There are now questions from the defence.
Dr Piper admitted that he can’t confirm whether the drug was taken [by Helen] knowingly or not. Hair is assumed to grow at 1cm a month, that is the recognised average, jurors are told. Dr Piper has admitted that all his answers are based on the assumption that Helen Bailey died on April 11, 2016.
Earlier sample could be 'axial diffusion'
A very low level of Zopiclone was found in Helen’s hair from early December 2015 - but this could be due to ‘axial diffusion’, he added.
