A man who murdered a nine-year-old girl by stabbing her in the heart while she played with a hula hoop in the street has been jailed for life with a minimum term of 25 years.

Lilia Valutyte was attacked by Deividas Skebas, 26, in the town centre of Boston, Lincolnshire, on 28 July 2022, while she was playing outside her mother’s embroidery shop.

A trial heard there was no dispute that Skebas, who has been diagnosed with schizophrenia, killed Lilia, but a jury was asked to decide what his state of mind was at the time of the attack.

The Lithuanian defendant, who told police he was being controlled by Nasa, admitted manslaughter on the grounds of diminished responsibility but was convicted of murder by a jury, who were shown CCTV footage of the act, at Lincoln crown court on 5 February.

Skebas appeared by video-link from Rampton hospital, a high security psychiatric hospital in Nottinghamshire, and stared ahead without reacting as his sentence was read out by Mr Justice Choudhury on Wednesday.

Deividas Skebas had previously admitted manslaughter on the grounds of diminished responsibility, but was found guilty of murder. Photograph: Lincolnshire Police/PA

Skebas had entered the UK legally three weeks before killing Lilia and was working as a fruit picker.

At the trial’s conclusion, Lilia’s mother, Lina Savickiene, in a victim impact statement read out by her husband and Lilia’s stepfather, Aurelijus Savickas, wrote that the grief the family had suffered was “not something you recover from”.

Savickiene, who found her daughter after the attack and cradled her body, wrote that “sometimes terrifying thoughts overwhelm the mind and during this trial there have been many, many more. Why her? Why us? The questions remain unanswered.”

During the trial, the prosecutor Christopher Donnellan KC said “this deliberate murder was clearly a wicked act” and that Skebas was aware of the severity of the crime when he committed it, adding: “He knew his conduct was wrong. He knew he was killing a child.”

Representing Skebas, Andrew Campbell-Tiech KC told the jury there was no debate about the fact that his client had killed Lilia, but that his mental state meant he should be convicted of manslaughter on the grounds of diminished responsibility, which he had previously admitted.

Campbell-Tiech described Skebas as “quite obviously deluded” and said that clinicians who had treated him doubted he would recover.

The court heard that after the killing, Skebas believed he had “the power to resurrect” Lilia but could only do so if the police contacted “his controller in Nasa”.