A “suspicious” vehicle that was seen at a vantage point overlooking the road where Daphne Caruana Galizia was murdered is being treated as a key lead, the Times of Malta has learnt.

The car is believed to have potentially been used by the person who detonated the powerful explosive device, according to sources involved in the investigation into the brutal car bombing on Monday afternoon.

It was seen parked in the middle of a country lane some distance from nearby buildings and raised suspicions among motorists.

The area where the car was spotted has since been cordoned off by police and extensively combed by a forensics team.

Sources said cigarettes and other pieces of evidence have been collected and sent for DNA testing.

Meanwhile, however, investigators said the country road was often used by motorists as a quick route to the Mġarr bypass.

“Although it is a lesser known road it does get used, particularly at the time the bomb was detonated – 3pm – it leads to a private school in Mġarr and is used by parents on their way to pick up their children,” the sources said.

One parent who passed through that road to pick up a child from school also drove right past the flaming wreckage of Ms Caruana Galizia’s rented car on the way back home.

“I saw a car on fire in a field just off the road in Bidnija. I had a young child in the car so I didn’t hang around in the cloud of black smoke,” the eyewitness said.

The witness said the area where the explosion had happened was littered with debris and seemed more like a scene from a war zone than the idyllic Bidnija countryside.

“At first I didn’t realise what I was driving through, it was bizarre but then it became clear,” the source said, reliving the “surreal sight”.

Investigators said work had started with the Federal Bureau of Investigation to triangulate mobile phone activity in the area and locate the exact spot the bomb was detonated from.

Sources said it was “almost certain” that the bomb had been triggered using a mobile phone, so they are hopeful to have a definitive idea of the killer’s location at the time of the murder.

Meanwhile, sources said the police were yet to receive any tangible information that could help solve the case.

The sources played down revelations by Home Affairs Minister Michael Farrugia that a tipster had come forward, saying there had been contact with a civilian but the information was not deemed valid to the inquiry.

The police urge anyone with any information that could help the investigation to come forward.