Tonight's fascinating BBC documentary, A Prescription for Murder?, explores the massacre of 12 people watching The Dark Knight in a Colorado cinema by James Holmes.
The programme will go into detail about whether an SSRI antidepressant – prescribed by a doctor – played a part in the killings by the young man.
With exclusive access to psychiatric reports, police footage and drug company data, reporter Shelley Jofre investigates the mass killings at the 2012 premiere of the Batman movie in Aurora, Colorado.
It seemed bizarre that 24-year-old PhD student Holmes would murder 12 people and injure 70 others in the mass shooting, and the SSRI anti-depressants he had been prescribed could be partly to blame for the killings.
Along with the case the documentary will explore the devastating side effects of being prescribed SSRI anti-depressants that may lead to psychosis, violence and even mass murder.
Common side effects of the drug include feeling agitated, shaky or anxious, feeling or being sick, indigestion and blurred vision among many others.
Holmes had carried out the killings with an arsenal of weaponry he had accumulated in the preceding weeks – planning the shootings down to the tiniest detail. He even booby-trapped his own apartment with homemade bombs to divert police resources while he launched the attack.
A recording of his interview just hours after the attack shows him slumped nonchalantly across the desk from the detectives with messy red-dyed hair and undone clothing, looking like a monster perfectly capable of committing one of the worst mass shootings in recent US history.
When asked to spell his surname during the interview, he cockily replied: "Like Sherlock".
At one point he was left alone with paper bags on his hands to secure forensic evidence and was caught on camera using them to talk to one another like sock puppets.
The spree killer, now 29, was hospitalised after attempting suicide several times while in jail. He entered a plea of not guilty by reason of insanity. His trial began in April 2015 and on 24 August he was sentenced to 12 consecutive life sentences plus 3,318 years without parole.
A Prescription for Murder? airs tonight (26 July) at 9pm on BBC1.