Ambulances were still rushing to and from Valletta Road in Żurrieq when court experts and the magistrate arrived on the scene. 

Barely one hour earlier, an open-top double-decker tourist bus had struck a tree, killing two and injuring 50. On Tuesday morning, nine of those, including three children, remained hospitalised. 

Magistrate Monica Vella is leading an inquiry into the case, and she must now piece together the puzzle and make sense of what exactly caused the 4.15pm tragedy. 

Initial reports suggested the bus had brushed past low-lying branches which struck passengers seated on its top deck. A police statement issued shortly before 6pm on Monday was less specific, saying simply that a Dennis Trident double-decker bus had hit a tree. 

With police having cordoned off the crash site, reporters who rushed to the scene of the incident were initially unable to get a close look at the tree in question. 

By Tuesday morning that was no longer the case, and photos of the impact-scarred tree suggest that rather than branches, the double-decker hit one of the tree's lower boughs. 

Times of Malta photographer Matthew Mirabelli waited patiently at the collision site until a tourist bus much like the one involved in Monday's crash drove past. 

The bus was empty, though when Times of Malta rang up City Sightseeing Malta and posed as a potential passenger, a customer service representative said bus tours were running according to their normal schedule. 

As the Tuesday morning bus drove past the Valletta Road tree, its driver steered the vehicle towards the centre strip

As the Tuesday morning bus drove past the Valletta Road tree, its driver steered the vehicle towards the centre strip. In so doing, they provided a sense of perspective by which to assess Monday afternoon's crash.

The photos suggest the double-decker was on the near side of the road when it drove beneath the tree, past the road's outer demarcation line and alarmingly close to crash barriers.  

They may also point to a tree which is too low for a double-decker bus to safely pass under - or a road that is too narrow to safely accommodate such a vehicle when it is facing oncoming, possibly overtaking, traffic. 

Magistrate Vella and her team of experts must work through these questions and several others as they compile their report into the incident. 

Meanwhile, the bus' shocked 24-year-old driver was discharged from hospital early on Tuesday afternoon, and promptly arrested by police.