Two political figures who previously held powerful government roles in Malta were accused of plotting to kill the journalist Daphne Caruana Galizia during court testimony on Wednesday.

The allegations, against a former economy minister and a former chief of staff to the prime minister, were made during a chaotic day at the courts of justice in Valletta, where the businessman Yorgen Fenech is on trial for ordering the assassination of Caruana Galizia in 2017.

The jury heard from brothers George and Alfred Degiorgio, underworld figures who confessed to planting the car bomb that killed the journalist and are serving 40-year sentences.

The two men named the former economy minister Chris Cardona and Keith Schembri, who as the then chief of staff to the prime minister was Malta’s most powerful unelected government official, as “involved” in the murder. They also named an associate of Cardona, the lawyer David Gatt.

First to give evidence was Alfred Degiorgio, who was brought from prison to testify. He told the court: “Before I testify, I want to say that Chris Cardona, David Gatt and Keith Schembri are involved in the murder”.

Degiorgio did not elaborate further. He claimed he could not testify as he was contesting his sentence in the European court of human rights. Over the course of the morning, he was questioned by lawyers for the defence and for the prosecution. Each time, he responded saying: “I will not answer”.

The judge, Edwina Grima, ordered Alfred Degiorgio’s arrest for contempt of court and arraigned him to return for a hearing on the matter within 48 hours.

George Degiorgio testified in the afternoon, and the jury heard a series of detailed allegations.

He claimed: “The murder started in 2015,” and later added “In 2015, it was Chris Cardona who gave me the orders.”

Recalling the alleged earlier plot, he said: “I was at home. David Gatt called me and said he wanted to have a word. I went to the potato shed and we met there. He told me ‘Come with me, Cardona wants to speak to you’ … Cardona was at a bar, seated at a Red Bull table. We had a drink and he told me ‘I want you guys to kill Daphne’. I asked him who Daphne was, and he told me David [Gatt] would explain.

“I told him it would cost €150,000 …”

“I asked him [Cardona] who was involved and he said ‘me, Keith, the commissioner and someone else’. He said he didn’t know the other person.”

George claimed Cardona wanted the journalist killed “because she’ll break our party”. Cardona and Schembri were members of the administration of the prime minister Joseph Muscat, who as head of the Labour party, ended a long period of Nationalist party rule in 2013. By 2015, Caruana Galizia had published a number of investigations into Muscat’s administration.

George claimed that after about five days, he was again taken to meet Cardona, who handed him €50,000 in cash. He said the recruited associates started spying on the journalist’s home but stopped after a police patrol car drove past their vantage point.

He said he complained, and a few days later Cardona came and told him “You can continue, police won’t be passing from there anymore.” Degiorgio told the court he assumed Cardona has spoken to the police commissioner.

He alleged the murder plot was then stopped at the request of Gatt. “We knew where we were going to kill her … then David Gatt came and told us to stop everything because an election was coming, some early election.”

The only elections held that year were council and European parliament elections, in April 2015.

Degiorgio said the plan was to stop Caruana Galizia in the road and shoot her. When the plot was called off, he alleged Gatt told him to “keep the money, I’ll sort it out.”

During his testimony, George avoided talking about the 2017 killing, citing his own challenge at the European court of human rights. However, he claimed Cardona and Schembri were also behind the 2017 plot, alleging it was confirmed by Cardona himself.

Exchanges became heated when George was challenged by the prosecution about why he had not, during his previous sworn testimonies, named the two men in connection with the later 2017 plot. He shouted at the prosecution lawyer before turning to the jurors to say: “Be careful.”

Judge Grima intervened, finding him guilty of contempt of court and fining him €500.

“Make it €1,000 instead of €500,” Degiorgio shouted in response.

Cardona, Schembri and Gatt have previously denied any involvement in Caruana Galizia’s death.

In a statement released on Tuesday, Caruana Galizia’s family said: “The defence appears to be inviting the jury to consider whether responsibility of Daphne’s assassination lies elsewhere; that the mastermind is not Yorgen Fenech but rather Keith Schembri or Chris Cardona. But allegations alone are not evidence.

“No sufficient evidence has been presented in court showing that Keith Schembri or Chris Cardona paid for Daphne’s assassination.”

Transcripts and translation by Amphora Media