A year after Daphne Caruana Galizia's gruesome murder, the three men suspected of carrying out the killing were back in court for the compilation of evidence.

Highlights from Thursday's court case:

• Defence lawyers tried to dig holes in the testimonies of a chemical expert and mobile phone company employees.
• Witness says a small amount of TNT was found in a street crater and the floor board of the vehicle. 
• Defence raises questions after it emerges that the university lab used for testing was not accredited.
• Journalists were twice ordered to leave the court room.

2pm: After the adjournment, we see some tension in the court room. The defence says it has filed another constitutional case about this issue, claiming the prosecution are on a fishing expedition.

Deputy AG Philip Galea Farrugia says that such constitutional cases have a stultifying effect on the proceedings.

1.55pm: After almost three-and-a-half hours, the case is adjourned to December 5. Magistrate insists that prosecution is to summon "considerable number of witnesses" on that day to make full use of time available. 

1.51pm: After further discussion between the police inspector, the defence lawyer and the magistrate, the witness is told to supply data linked to all numbers connected to each tower indicated by prosecution in their original request to Vodafone. Today, witnesses limited their report to some five numbers specified by the prosecution. 

1.40pm: Back in the court room, the witnesses discuss the location of the cell towers, and call data records. 

1.25pm: Reporters are once again asked to leave the court room. 

1.23pm: Why is the mobile phone data essential to the case?

Last December, Inspector Keith Arnaud told a court that all bar one of the SIM cards police were looking into as part of the murder investigation went silent once the fatal bomb went off. That one remaining SIM card was tracked to a cell tower in Marsa, and matched the times with CCTV footage of Alfred Degiorgio's boat, Maya, returning to the Grand Harbour.

1.20pm: "How did prosecution conclude that this tower was linked to a call from sea? Did they get it from Vodafone?," the lawyer challenges. 

Witness replies: "We were asked for coverage map of that particular site."

Inspector Arnaud objects, saying the question does not involve this witness.

1.17pm: As the defence lawyer tries to question the reliability of phone data, the engineer hits back: a mobile sends out a signal even when not used, and it does so every hour or so.

1.13pm: In cross examination, defence lawyer William Cuschieri asks how could calls be linked to the Bidnija cell tower when it was switched off just after 3pm on the day of the murder. The engineer replies that the tower might have been switched on at certain intervals. He adds that this is a continuous process as part of the maintenance work required on the network.

1.05pm: The sitting has resumed with engineer Mario Cordina from Vodafone taking the witness stand. He explains to the court how cell towers are named according to particular landmarks.

12.30pm: Reporters are back in the court room but the court has just adjourned the sitting for a short break. 

12.18pm: It's the first time that reporters have been ordered out of the court room since the compilation of evidence against the three men started last year.

12.05pm: Reporters are asked to leave the court room as court decides data detailed in the mobile phone witnesses’ report is not to be made public.

11.58am: Some background: Data from the Bidnija area helped investigators identify a phone number that received an SMS at 2.58pm on October 16, exactly when the bomb went off, then vanished from the grid.

This was the first step in a long and complicated ‘data trawling’ investigation.

Deeper analysis of the cell tower data shows that the SIM used in the bomb went active in the Bidnija area at around 2am on October 16 – which is when investigators believe the bomb was placed in Ms Caruana Galizia’s car.

11.46am: A Vodafone engineer says that on the day of the murder one of the cell towers at Bidnija had been switched off for upgrade purposes. There was no activity from this tower after 3.05pm. The explosion took place just before 3pm. 

11.45am: Defence lawyers say they want to cross examine the Vodafone witness before he leaves the court room. But police inspector Keith Arnaud firmly stands his ground. First he must finish his questions, then the cross examination.

11.32am: Mobile signal information, which records times when devices were switched on and off, had been requested by the police, the witnesses say.

Even when not in use, a device exchanges information with networks every hour or so.

11.25am: Meanwhile, two Vodafone employees take to the witness stand but defence lawyer insists they are to testify separately.

An engineer explains the technical information in the report detailing call data records. The report is 22 pages long.

Read: How phone data helped police home in on suspects

11.20am:  It's clear that the defence is trying to shed doubt on the conclusions of the chemical expert by pointing out that the university lab was not accredited. 

11.11am: Lawyer Martin Fenech now asks the court for an on-site inspection of the University lab where tests were carried out.

"Why was this lab not accredited?," he asks.

The magistrate agrees to the request but within the context of the particular tests carried out. It would have been different had it been a DNA test where even a hair can influence the outcome of the tests, the magistrate adds.

Dr Fenech insists that factors inside the lab, such as air conditioning, might impact the tests.

11am: Defence lawyer and expert are engaging in a debate whether the lab was specialised enough to host the tests.

"So is this a homemade lab? Is this where the tests were carried out? What guarantee do we have?," the lawyer hits out.

The magistrate intervenes, asking whether the tests were verified by the Netherlands Forensic Institute for peace of mind. The expert replies: "yes".

10.58am: Defence lawyer asks for the expert's qualifications. Dr Vella is a PhD graduate. The lawyer also challenges the expert to explain how he gathered the evidence on site. 

The tests were carried out at the university's chemistry department laboratory.

10.48am: Taking the witness stand, Dr Daniel Vella says he helped police to collect evidence to determine post blast residues on site, the day after the blast which claimed the journalist's life. He went again the next day to collect parts of the vehicle torn apart by the explosion. 

A small amount of TNT was found in a street crater and the floor board of the vehicle. The expert presents a report detailing his findings. 

10.42am: Once again there's tight security around the court building as the murder suspects are escorted to court. 

10.40am: Present in the courtroom is Dutch MP Pieter Omtzigt, who is tasked with preparing a report for PACE on the investigation into the assassination of Caruana Galizia and the rule of law in Malta.

What we know so far:

• Ms Caruana Galizia was killed in a car bomb blast on October 16, close to her home in Bidnija.
• In December, police arrested 10 men in connection with her murder.
• Three of those - Degiorgio brother Alfred and George, and Vincent Muscat - were charged with her murder. The others were released on police bail without charge.
• The bomb - between 300gr and 400gr of TNT - was an improvised explosive device clearly intended to kill the journalist.Forensic experts say there was metal shrapnel embedded in Daphne Caruana Galizia's body.
• National security information system unit officer explained how information was collated from the various calls, determining the time and location they were made.
• The FBI helped to home in on suspicious phone numbers. One was linked to a remote-controlled device and went active at 2am in Bidnija on the day of Ms Caruana Galzia's murder. It received an SMS at the time the bomb went off and immediately went off-radar.
• Triangulated cell tower data to work out that the killer SMS was sent from out at sea. George Degiorgio was seen going fishing on that day, and shortly after the bomb went off texted his partner "buy me wine, my love."
• Experts received reports of a suspicious car regularly parked by tat-Tarġa Battery - an ideal vantage point for the killers - in the days leading to the murder. The car was subsequently never seen there again.
• Police found a "fresh-looking" cigarette butt with Alfred Degiorgio's DNA on it under a tree at the tat-Tarġa vantage point.

The key courtroom players:

Martin Fenech is appearing for Vince Muscat, known as il-Koħħu, 55.

William Cuschieri and Martha Muscat are appearing for Alfred Degiorgio, known as il-Fulu, 53.

Josette Sultana is appearing for Alfred's brother George Degiorgio, known as iċ-Ċiniz 55.

Philip Galea Farrugia from the attorney general's office and inspectors Keith Arnaud and Kurt Zahra are appearing for the prosecution.

Jason Azzopardi and Therese Comodini Cachia are appearing parte civile.

Read: Who was Daphne Caruana Galizia?