The prosecution of Brandon John Rainey regarding the death of 21-year-old Chloe Mitchell has become a case in which expert witness, psychiatric evidence may prove central to the eventual determination of criminal responsibility.
Mitchell disappeared in Ballymena, County Antrim, in the early hours of June 3, 2023. She had last been seen on CCTV in Ballymena town centre. An extensive search followed, and suspected human remains were discovered several days later. Police subsequently launched a murder investigation, and Rainey was arrested and charged with murder. He also faces an allegation of attempting to prevent the lawful and decent burial of a deceased body.
The case has since taken a number of unexpected turns. Rainey initially denied murdering Mitchell and was due to face trial at Belfast Crown Court. In February 2026, however, his legal team told the court that he accepted killing Mitchell but intended to rely on diminished responsibility. This distinction is vitall: the issue is no longer simply whether Rainey was responsible for Mitchell’s death, but what his mental state was at the relevant point in time and whether the evidence supports the statutory defence.
Psychiatric Evidence
The medical evidence has already involved several psychiatric assessments.
Dr Issac, instructed for the defence, had previously examined Rainey and produced a psychiatric report. The Crown told the court that Dr Issac’s report had been leaned upon as far back as April 2025. Following Rainey’s change of instructions, defence counsel required an updated assessment and addendum report because the case had effectively become a medical defence based upon diminished responsibility.
The publicly available court reporting does not disclose Dr Issac’s full qualifications or the detailed clinical conclusions contained in his confidential report. It would therefore be inappropriate to attribute a specific diagnosis or opinion to him beyond what has been disclosed in court. What is clear is that his assessment is potentiallyinherently important to the defence case because his opinion concerns Rainey’s mental state and the proposed diminished-responsibility defence.
The Crown has also instructed Dr Brennan, a psychiatrist, to examine Rainey. The prosecution made it clear that its position would depend upon updated medical evidence from both Dr Issac and Dr Brennan. Dr Brennan had previously been unavailable because of leave, with an examination expected to take place after his return.
The state of affairs creates a familiar forensic-psychiatric structure: the defence expert assesses the accused’s mental state and the Crown obtains an independent assessment against which the defence opinion can be tested. If the opinions diverge, the court may have to determine which evidence is better supported by the clinical history, contemporaneous evidence and accepted psychiatric methodology.
Expert Witness, Dr Richard Latham
More recently, the defence instructed a consultant forensic psychiatrist, Dr Richard Latham. His report has become one of the outstanding pieces of evidence delaying the final preparation of the case.
Dr Latham is not simply a clinician with general psychiatric experience. Public professional material identifies him as a Consultant Forensic Psychiatrist, with experience in mental illness, personality disorder and intellectual-disability services. He has also worked extensively in forensic and prison mental-health settings. The Royal College of Psychiatrists has identified him in its Forensic Psychiatry Faculty publications, while professional material records his NHS role and forensic psychiatric practice.
His professional background is particularly relevant in a case involving an accused person held in custody and an assessment of mental state in the context of alleged criminal conduct. Dr Latham has considerable experience of the difficulties involved in reconstructing a defendant’s mental state at the time of an alleged offence.
At the August 14 review hearing, the defence told the court that Dr Latham’s psychiatric report was expected by the end of August 2026. The court was therefore still awaiting his opinion before the case could be fully advanced towards trial.
It is important, however, not to confuse professional expertise with a known finding in this case. Dr Latham’s conclusions concerning Rainey have not been publicly disclosed, and it would be premature to suggest that he has reached a particular diagnosis or conclusion concerning diminished responsibility.
Psychological Assessment
The Crown has now gone further by commissioning a psychologist to examine Rainey. At the August hearing, prosecution counsel David Russell KC told the court that arrangements had been made for the psychologist to visit Rainey at Maghaberry Prison on August 27 and 28. The Crown was awaiting confirmation that Rainey would agree to see her, having previously refused the proposed examination.
The psychologist’s identity has not been publicly disclosed in the court reporting available at present. Nor have any conclusions been reported. The involvement of both psychiatric and psychological experts underpins the evidential complexity of the case. A forensic psychiatrist may address diagnosis, mental disorder, treatment and the relationship between a disorder and criminal responsibility, while a forensic psychologist may contribute assessment of cognitive, behavioural and psychological functioning. The precise questions put to each expert will ultimately depend upon the issues identified by the parties and the court.
The Next Stage
The inherent priority is completion and disclosure of the outstanding expert evidence. Dr Latham’s report is expected at the end of August. The Crown’s psychologist is scheduled to assess Rainey at Maghaberry on August 27–28. There is also outstanding disclosure concerning a statement from another Maghaberry prisoner who reportedly recounts conversations with Rainey.
Once the reports have been served, counsel will have to consider whether there is a genuine dispute between the experts. If there is, the experts may eventually be required to give oral evidence and face cross-examination concerning their methodology, factual assumptions, diagnostic reasoning and ultimate conclusions.
The judge has indicated that a trial date will be fixed at the next review once these outstanding matters have been resolved. The court is plainly anxious to prevent further delay: Rainey’s trial had originally been listed for earlier in 2026, but changes in legal representation, medical assessments and disclosure have repeatedly affected the timetable.
For expert witnesses, the case demonstrates the importance of careful retrospective assessment. Where an accused’s mental state at the time of an alleged offence is disputed, the expert is rarely able to rely solely on a contemporaneous clinical examination. Instead, the opinion may have to be reconstructed from medical records, witness accounts, behaviour before and after the alleged offence, police material, interviews and the defendant’s own account.
The eventual court determination will therefore depend not simply upon which psychiatrist has the more persuasive professional credentials, but upon the evidential foundation for each opinion but past data.
At present, the most significant expert evidence remains outstanding. Dr Issac’s earlier assessment, Dr Brennan’s Crown assessment, Dr Latham’s forthcoming psychiatric report and the newly commissioned psychological examination will collectively shape the medical case. Until those reports are disclosed and scrutinised, it is not possible responsibly to predict whether the diminished-responsibility argument will succeed.
What is clear is that the forthcoming stage of the proceedings will be heavily dependent upon expert witness evidence—and that the competing interpretation of Rainey’s mental state may become one of the defining issues when the case eventually reaches Belfast Crown Court.
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