Assistant Police Commissioner Keith Arnaud, the officer who led the investigation into the assassination of Daphne Caruana Galizia, on Friday spent an entire day guiding jurors through the police investigation that began within minutes of the 16 October 2017 car bomb attack and eventually led investigators from the hitmen to middleman Melvin Theuma and, ultimately, businessman Yorgen Fenech.

Testifying before Judge Edwina Grima on the third day of Fenech's trial by jury, Arnaud largely revisited evidence already presented during the compilation of evidence, explaining chronologically how investigators pieced together telecommunications data, forensic evidence and witness testimony to arrive at the perpetrators.

Fenech, 44, has pleaded not guilty to complicity in the wilful homicide of Daphne Caruana Galizia and criminal association to commit the murder.

Nearly nine years after the assassination of Daphne Caruana Galizia, a columnist for The Malta Independent, the jury hearing the case against businessman Yorgen Fenech was taken through the investigation that transformed what initially appeared to be another car bomb attack into one of Malta's most significant criminal investigations.

Arnaud, who headed the investigation while serving as an inspector within the homicide squad, began by describing the immediate response after police received reports of an explosion in Bidnija shortly before 3pm on 16 October 2017.

He and fellow investigator Kurt Zahra rushed to the scene, where officers first secured the area before confirming that the victim was Daphne Caruana Galizia.

Although Malta had already experienced previous car bomb attacks, investigators immediately realised this case required an extensive forensic and technical investigation.

Police quickly established two priorities: preserving every possible piece of forensic evidence and determining how the explosive device had been triggered.

The scene was deliberately left largely untouched until foreign experts could arrive. The FBI and Europol were called in to assist while members of the Armed Forces guarded the area for days to ensure no evidence was contaminated.

Investigators reconstructed the vehicle's path after the explosion and recovered fragments of the bomb. Forensic analysis later established that TNT had been used.

Attention immediately turned to how the killers had monitored their victim before detonating the device.

Matthew Caruana Galizia, the victim's son, informed investigators that his mother had briefly returned home to collect a forgotten chequebook before driving away again moments before the explosion, providing investigators with a narrow timeframe.

Police began searching for possible lookout positions overlooking the family's home and discovered two likely observation points, including one near the Victoria Lines, Arnaud testified.

A witness proved particularly significant after reporting that a small vehicle had repeatedly been seen parked near one of these vantage points in the days leading up to the murder. Investigators later discovered a concealed observation position with a direct view of the Caruana Galizia residence and the stretch of road where the explosion occurred.

Among the physical evidence recovered from the area was a discarded cigarette butt. DNA analysis later established that it belonged to a man, Arnaud said.

Alongside the forensic investigation, police began an enormous analysis of telecommunications data.

With assistance from the FBI, investigators examined thousands of mobile phone numbers that had connected to nearby mobile phone masts around the time of the explosion.

Gradually, three telephone numbers began attracting investigators' attention.

One device remained in the Bidnija area before the explosion, while another operated from the Grand Harbour area. Analysis revealed that one SIM card had been inserted into a device capable of remotely triggering another mechanism through an SMS command rather than being used as a normal mobile phone.

The devices communicated almost exclusively with each other.

Investigators reconstructed the communications between them, identifying what they believed were test activations weeks before the murder before concluding that an SMS sent shortly before 3pm on 16 October had triggered the bomb, Arnaud said.

The movement of the second device also suggested its user was at sea because it connected rapidly to successive mobile phone masts around the Grand Harbour.

Further analysis gradually pointed investigators towards Alfred and George Degiorgio, Arnaud said.

The burner phones repeatedly connected to mobile masts covering St Paul's Bay, where the brothers lived, while one of the devices had also been traced to the Marsa potato shed already associated with them.

Investigators also knew George Degiorgio owned a boat, Maya.

A reconstruction exercise comparing CCTV footage taken on the day of the murder with new recordings convinced investigators that Maya was the same vessel seen leaving the Grand Harbour early on the morning of the attack, remaining stationary beneath the Upper Barrakka around the exact time of the explosion before returning to Marsa.

Telecommunications analysis eventually enabled police to identify all three users of the burner phones, linking them to George Degiorgio, Alfred Degiorgio and Vince Muscat.

Arrest warrants were subsequently issued for the three men as well as others suspected of assisting them, including Robert and Adrian Agius.

Arnaud described the December 2017 operation in which police arrested ten suspects at the Marsa potato shed rather than the five originally targeted.

Searches recovered several mobile phones, including the burner phone linked to George Degiorgio.

The three principal suspects remained silent during interrogation before being arraigned.

Arnaud told the court that at this point investigators knew the inquiry into the assassination was far from over.

The crucial question remained whether the men arrested had acted on their own or on behalf of someone else. Investigators therefore began searching for the motive behind the murder.

Police examined Caruana Galizia's published work but found nothing that adequately explained the assassination. This led investigators to suspect she may have been killed because of information she was working on but had not yet published, Arnaud said.

Attention also focused on communications involving the Degiorgio brothers.

Police monitored prison visits, telephone calls and deposits into prison accounts.

Investigators repeatedly noticed the brothers asking their sibling Mario whether an unnamed individual had visited him.

Arnaud described another significant breakthrough when lawyer Arthur Azzopardi contacted him to say Vince Muscat wished to cooperate with investigators. The meeting took place discreetly because of security concerns.

Muscat's subsequent account, Arnaud testified, matched evidence already independently gathered by investigators.

According to Arnaud, Muscat confirmed details already established through forensic and telecommunications evidence, including surveillance locations, the cigarette butt recovered near Bidnija, the initial plan to shoot Caruana Galizia before switching to a car bomb, rehearsals using a rented vehicle and the use of mobile phones during the attack.

Muscat also described how Alfred Degiorgio had met Melvin Theuma after being offered €150,000 for the murder. Theuma did not reveal who was financing the assassination, Arnaud testified.

According to Arnaud, Muscat further recounted driving Alfred Degiorgio to collect the deposit and later to receive the final payment. Muscat had admitted having second thoughts at one stage but nevertheless remained involved.

According to Arnaud's testimony, Muscat also described how the conspirators tracked Caruana Galizia after learning she regularly visited a coffee shop in Naxxar.

The group later rented garages in Mosta and Santa Venera.

Investigators simultaneously intensified surveillance on Melvin Theuma, whom they increasingly believed was acting as an intermediary.

Police observed frequent contact between Theuma and Mario Degiorgio after the arrests, with investigators believing Theuma was reassuring the imprisoned brothers through Mario.

As the investigation developed, police learned that Theuma had secretly recorded conversations and appeared increasingly anxious.

Arnaud described how investigators became divided over strategy.

Some favoured arresting Theuma immediately.

Others, including Arnaud, believed patience offered the better chance of recovering potentially crucial recordings.

Arnaud explained that arresting Theuma prematurely without obtaining the recordings risked forcing police to release him, thereby alerting him to the investigation.

Instead, investigators adopted a different strategy.

After discovering Theuma's involvement in illegal betting, the Economic Crimes Unit developed a money laundering investigation that would provide lawful grounds to arrest him without revealing police suspicions regarding the murder.

Meanwhile, Arnaud increasingly devoted himself exclusively to the Caruana Galizia investigation, reporting directly to the Police Commissioner after changes within the investigative team.

The money laundering investigation culminated in November 2019.

Police originally intended arresting Theuma on 16 November but brought the operation forward by two days.

Arnaud vividly described Theuma's behaviour after his arrest.

Rather than the "tough guy" investigators had expected, Theuma appeared emotional, repeatedly breaking down in tears and saying he had considered approaching police himself.

He told investigators he possessed an ice cream container holding material connected to the murder. Theuma requested the presence of a lawyer before speaking.

Once the inquiring magistrate arrived, the container was formally opened and found to contain three mobile phones, a voice recorder, USB devices, photographs of chats and a photograph depicting Theuma with Keith Schembri, who was then the chief of staff in the office of the Prime Minister, Joseph Muscat.

Arnaud told jurors that investigators deliberately avoided immediately questioning Theuma about references to Yorgen Fenech that had already emerged from Signal messages.

Instead, discussions centred on securing a presidential pardon.

Under the eventual agreement, Theuma was obliged to disclose everything he knew about the assassination, including who committed the murder, who financed it, how much money changed hands and everyone involved.

Once the pardon was formally granted on 19 November 2019, Arnaud said, Theuma began telling investigators everything he knew.

Arnaud told jurors that Theuma became increasingly fearful after Vince Muscat began cooperating with investigators. Although the Degiorgio brothers did not know Fenech's identity, they knew Theuma was the intermediary between them and whoever had commissioned the murder. Fearing he could become the only person implicated, Theuma began secretly photographing and recording conversations with Fenech as a form of protection.

Investigators recovered documents which, Arnaud said, corroborated Theuma's account. Among them was a handwritten receipt from lawyer William Cuschieri acknowledging funds for the Degiorgio brothers' legal fees, together with records allegedly detailing cash passed from Fenech to Theuma. Arnaud testified that Theuma had carefully retained the receipts to prove to Fenech that the money had been delivered and not kept for himself. According to Arnaud, investigators concluded that almost half a million euro had been channelled through Theuma to support the Degiorgios' legal expenses, food and other needs while they were in custody.

Arnaud then recounted what he said was Theuma's account of how the murder plot originated. According to Theuma, a meeting took place at the Blue Elephant restaurant in Portomaso around three weeks before the 2017 general election was called. During that meeting, Theuma alleged, Fenech asked whether he knew George Degiorgio before stating that Daphne Caruana Galizia had to be killed because she supposedly possessed information concerning his uncle, Ray Fenech.

Theuma told investigators he subsequently contacted Alfred Degiorgio, eventually proposing the murder for €150,000 after meetings in Marsa and at Busy Bee in Msida. Fenech accepted the price. However, once the general election was announced, Arnaud said, the plan was temporarily put on hold until a further go-ahead was given.

According to Arnaud's testimony, Theuma also claimed Fenech later arranged for him to meet Keith Schembri at Castille, after which he began receiving monthly government payments despite performing no work. Theuma said the payments stopped after seven months.

Arnaud also told jurors that Theuma alleged Fenech eventually handed him €150,000 in cash in a brown envelope following Labour's election victory, after an initial €30,000 deposit had already been paid. Theuma said he retained the money until the murder was carried out and continued supporting the Degiorgio brothers financially even after he had begun cooperating with investigators.

The witness added that, according to Theuma, Fenech later admitted that Caruana Galizia had been about to publish information concerning him personally, leading Theuma to conclude that the explanation previously given about Ray Fenech had been false. Days after the murder, Theuma allegedly told Fenech he was becoming increasingly frightened, particularly after learning through media reports that the FBI had joined the investigation.

Arnaud's testimony continues this morning.

For aminute-by-minute account of today's court proceedings click here