As the investigation progressed, police discovered that Thomas had a history of dishonesty and had previously made false reports of crimes. They also found inconsistencies in her story and a lack of emotional response to the disappearance of her daughter.
The trial of Tessa Thomas began in 2011. The prosecution presented evidence that Thomas had intentionally killed Gemma, citing expert testimony and forensic evidence.
On the evening of December 24, 2009, Thomas claimed that she had left Gemma in her Moses basket while she went to get a nappy from another room. When she returned, Gemma was gone.
In 2011, Tessa Thomas was arrested and charged with the murder of baby Gemma. The prosecution alleged that Thomas had killed Gemma, possibly on December 23, 2009, and then fabricated the story about leaving her in the Moses basket.
The police were immediately notified, and a massive search operation was launched to find baby Gemma. The investigation, led by the Hertfordshire Police, included reviewing CCTV footage, interviewing witnesses, and conducting door-to-door inquiries.