The trial of four people arrested in connection with the murder of Becky Watts continues hearing evidence today. Nathan Matthews and Shauna Hoare deny kidnapping and murdering the teen. James Ireland and Donovan Demetrius deny assisting an offender.
Follow @ITVBeckyTrial for live updates from the court.
A Territorial Army member has said she thought Matthews had an anger problem, and would often "snap" while on training.
Danielle Rogers, who was a member of the TA alongside Matthews in 2006/7 told the court there were times he would worry her. She said Matthews would drive the pair to training, in Cardiff, and often take his anger out "on his driving".
She said it would never frighten her, but she was worried.
Another TA recruit said she believed Matthews was a "quiet nice guy", while his Squadron Sgt Major said he was keen and willing to learn.
The court also heard how Matthews learned about using cat litter to "absorb liquids" and "decontaminate" with the TA.
The jury has been told that cat litter - or Fuller's Earth - was found piled on top of part of Becky's torso inside a box in a shed.
Roy Kempton, who was Squadron Sgt Major of the unit in 2006 said training would have included camouflage, concealment, army discipline, and chemical, biological and nuclear defence, including decontamination.
Ms Rogers echoed the statement.
Former Grenadier Guard and TA cadet instructor Darren Thomas taught Matthews in 2000 at a detachment in Cadbury Heath, Bristol.
Mr Thomas said cadets would have been told about the use of Fuller's Earth - a powder in cat litter - in covering chemicals and "absorbing fluids".
Nathan Matthews has confessed to killing his step-sister, although he denies murder, this is the prepared statement he handed police.
Confessing to the killing, Matthews said he had arrived at the family home with the aim of kidnapping the teen to teach her a lesson.