US radio host and prominent conspiracy theorist Alex Jones has been ordered to pay $100,000 (£76,000) in legal fees and court costs in a defamation case against him.

The case has been brought by the father of a child killed in the Sandy Hook mass school shooting in 2012.

Mr Jones has long claimed on his show and Infowars site that the attack was “completely fake” and a “giant hoax”.

Twenty children – all under the age of 10 – and six adults were killed.

• Sandy Hook parents sue for defamation
• School shooting: How it happened

In a 20 December ruling, Judge Scott Jenkins of Travis County District Court in Texas said Mr Jones and his lawyer had intentionally disregarded an October court order to produce witnesses and other materials to the plaintiff in the lawsuit, Neil Heslin, US media report.

Mr Heslin’s son, six-year-old Jesse Lewis, was killed in the shooting.

The judge said their failure to co-operate “should be treated as contempt of court”. In two separate orders issued the same day, the judge told Mr Jones to pay $65,825 and $34,323 in lawyer fees incurred by Mr Heslin.

Added to an earlier October order against Infowars, Mr Jones and Infowars have been ordered to pay $126,023.80 over the case, even before it reaches trial, reports say.

“It’s hardly a surprise that someone like Alex Jones would soon find himself in contempt of court, but now he is learning there are severe consequences to his utter disrespect for this process,” Mark Bankston, one of Mr Heslin’s lawyers, said in an email to the Daily Beast.

Mr Bankston is quoted as saying by the New York Times that he expects trial in the defamation case to be scheduled before the end of next year.

The lawsuit filed in Travis County by Mr Heslin alleges Mr Jones accused him of lying about holding his son’s body with a bullet hole in his head, according to the complaint.

The lawsuit was filed in Texas, where Mr Jones lives and works. Mr Jones is facing a number of lawsuits filed by several families of the victims.

Mr Jones had implied the parents were actors seeking to undermine laws allowing private gun ownership.

On 14 December 2012, 20 children – aged between five and 10 – and six staff members were killed at Sandy Hook when a gunman opened fire with a semi-automatic rifle before killing himself.

Parents of Sandy Hook victims who have spoken publicly about their experiences have been targeted by trolls, both online, as well as in person.