On calling at the door of his mother's apartment, near Madrid's Las Ventas bullring, Sánchez officers heard Gómez say calmly: "My mother's here. She's dead."
When they forced their way inside, they found a hellish scene, with body parts belonging to the murderer's mother packed into food containers inside the fridge and in other areas of the house.
Some police officers were reportedly physically sick when hearing Sánchez Gómez relate that he had killed his mother by strangling her during a dispute, sometime between late January and early February, before cutting up her body with a saw and kitchen knives.
"The idea was to make her body disappear," he said, admitting that he "occasionally" ate parts of her body, while storing others and throwing some out with the rubbish inside plastic bags. He also fed some of her to his dog, the court heard.
Ms Gómez had suffered a series of violent attacks at the hands of her son, and had had a restraining order placed on him.
It is not known whether he forced his way into the house or if his mother let him in.
Sánchez Gómez had been arrested a dozen times, usually for assaulting his mother. The most recent arrest before he committed murder was in August 2018 for violating the restraining order.
The investigation into Sánchez Gómez revealed that he had a record of psychiatric illness, considered to be suffering from a personality disorder which may have been aggravated by drug use. He was said to become violent if he did not take his medication, and had been admitted to a psychiatric unit three times at his mother's request.
However, according to media reports, Sánchez Gómez was granted voluntary discharges from these spells in institutions when it was considered that he was stable.
Mental illness and the lack of resources dedicated to psychiatric services in Spain's public health system has become a major talking point since the start of the Covid-19 pandemic, and the government revealed this month it was working on a plan to improve attention to children and young people with psychological problems.
Sánchez Gómez had claimed in court that he had heard voices in his head telling him to kill his mother and dismember her body, but the judge ruled that there was no evidence of "serious alteration in his understanding of reality to the point of nullifying his will and cognitive faculties".
