At about 4.40am on New Year’s Day, two men died in a collision on a high-quality stretch of the N26, near Ballina, Co Mayo. They were the first fatal road deaths of 2014.

In the months since, Peter Murtagh has been investigating this crash and its aftermath.

In the third instalment of a four-part series he looks at the hours and days after the crash, when the forensic investigator and the pathologist tried to establish exactly how the men had died – and why.

When Castlebar-based pathologist Dr Fadel Bennani listens to RTÉ Radio One's Morning Ireland over breakfast, he dreads to hear of a fatal road crash in Co Mayo."No crash? Thank God," he says, "because it is very traumatic to everybody."

Wednesday, January 1st, 2014, did not begin well for Dr Bennani.There were two bodies for autopsy.

An autopsy is the medical examination of a body to determine the cause of death. In Ireland, it is carried out frequently on the orders of a coroner when a death has occurred suddenly, violently or without obvious explanation. While the manner of Gearóid Scully and Terence Beagan’s deaths was evident, the precise cause was not immediately obvious.

As the Garda scenes of crime forensic investigator, Sgt Gabriel McLoughlin, set about examining the N26 crash site, mortuary technicians began preparing Scully and Beagan’s bodies for their autopsies.

The first thing that happens when a body arrives at the morgue is that it is lifted out of the removal shell. Bodies from vehicle crashes or accidents at work may come in body bags; those from a hospital or nursing home more usually come wrapped in a white sheet.

Using the corners of the sheet for purchase, or gripping the handles of the body bag, the corpse is lifted from the removal shell and onto a mortuary trolley and identity tagged – one tag attached to the left arm, another to the right ankle. In this way, no matter in which position the body is slid into the cold store press, head first or feet first, anyone opening the door will see immediately an ID tag.

Overriding importance is given to correct identification when a body enters the morgue. Thereafter, the priority is to establish cause of death.

A mortuary technician makes an initial inspection of the body. Any valuables are removed and given to the Garda or hospital staff and are accounted for.

A neck brace, a spring-like expanding collar, is placed on the neck of the corpse to prevent the head slumping. The head is also raised and a small pillar placed under the back of the skull.

A body scheduled for autopsy is photographed three times before the procedure begins. The first photograph is taken on admission; the second when clothes have been removed; the third after the body has been prepped for autopsy.

The body is covered by a white shroud which is folded over the arms, feet and face as the trolley is slid into the chilled compartment, which generally has shelving space for six bodies. The door is then closed until the pathologist arrives for the autopsy.

Scrunched

At the crash site on the N26, forensic scenes of crime investigator Garda Gabriel McLoughlin surveyed the scene. A visual inspection suggested that the point of impact between the two cars was wholly on one side of the road – on the left hand, northbound carriageway in the direction of Ballina.

A clear point of impact was suggested by a tyre skid mark and two adjacent scrape marks gouged into the tarmac surface in the centre of the northbound carriageway.

Debris, the detritus of two smashed cars – glass, broken light covers, pieces of plastic and carbon-fibre, nuts and bolts, and the various fluids associated with motor vehicles – was strewn across both carriageways. An elongated debris field fanned out some 10 metres on either side of the point of impact, and stretched back about 25 metres towards Ballina.

This suggested that the greater force at the point of impact came from the Mercedes, driven by Terence Beagan, as it smashed into the Skoda, driven by Gearóid Scully. The force pushed the Skoda completely off the road, into the pebbles at the road's edge and on to the grass verge beyond.

When it came to a standstill, Scully’s Skoda was over 12 metres away from the point of impact. It was still pointing in the direction it had been travelling – towards Ballina – whereas the Mercedes, coming from Ballina, had spun around 90 degrees and was facing back towards the town.

The fronts of both vehicles were almost totally destroyed by the impact. The entire front of Beagan’s Mercedes – headlamps, grill, bonnet – no longer existed as an identifiable section of the car. It had all been crumpled into nothing, like a sheet of oven baking foil, scrunched inside a fist into a tight ball.

The same was true of the Skoda, only more so. The driver’s side of the front had been pushed back so far that the driver’s door area no longer existed as an identifiable part of the vehicle. The inside of the car was wrecked: the engine block had burst through the dashboard into the rear seating area.

McLoughlin placed stand-up plastic number markers, one, two, three and four, on the road corresponding to the skid and scrape marks etched into the surface.

He took numerous photographs, close-ups of the two wrecks and panoramas of the roadscape, 150, 100 and 50 paces back from the scene.

He measured the width of the road. It was 7.4 metres wide and at the edge of either carriageway, a hard shoulder measured 2.8 metres wide.

All the information gave him the means to create a precision sketch of the crash site, which he included with 22 of his photographs as part of his forensic scene of crash report.

Examining the remains of both vehicles as best he could given their condition, McLoughlin concluded that both were entirely roadworthy prior to the crash and that their brakes were working.

How fast?

It was known from what paramedics Eddie Scully and Wolfgang Schmidt, eyewitnesses to the crash, had told the Garda that the Skoda had been travelling at about 80 to 90 km/h, well within the speed limit. McLoughlin did not know the speed at which the Mercedes was travelling and did not make an estimate.

The Irish Times asked TMS, a UK-based road safety consultancy with a 24-year track record that includes over 11,000 road safety audits in the UK and Ireland, to estimate the speed of the Mercedes, given a set of known facts.

We gave them the following information from the Garda forensic scene of crime survey and other sources: the Skoda was travelling at approximately 55 mph and weighed 1,450 kilograms; the Mercedes weighed 1,600 kilograms and, in a head-on impact, pushed the Skoda over 12 metres back from the point of impact, on a smooth, cold but dry tarmac surface.

The question for TMS was: what is the estimated speed of the Mercedes? Using what is described as a “momentum exchange equation”, TMS senior road safety consultant Robert Cyples estimated that the Mercedes, on hitting the Skoda, was travelling at 171.2 km/h, or 106 mph – almost twice the speed of the Skoda.

His face was perfect

Lorraine Devlin, partner of Gearóid Scully, arrived at the morgue in mid-morning to identify his body. Lorraine wanted to do it herself; she wanted to see "Skull" again.

The morgue, a single storey building to the side of Mayo General, has four distinct areas, linked by a single corridor.

There is a small office for the technicians; outside it is a table with its ledger recording the bodies admitted. There is a room into which bodies are brought before being placed in cold storage.

Off this is the autopsy room, all stainless steel and easily washed down surfaces. The final room off the corridor is a chapel-like prayer room where visitors can seek contemplative comfort.

“His face was perfect, there was a few scratches on his nose and that was it,” Lorraine recalled of Scully’s body when it was shown to her for identification. “You wouldn’t even know, like . . .” her voice trails away.

Later in the day, pathologist Dr Bennani got to work inside the autopsy room. It has two, stainless steel autopsy tables. Each has raised sides, and the working surface areas are tilted slightly so that any fluids flow to one end. Specialised lighting is above each table.

Around the walls are sinks, shelves and cupboards. The pathologist’s tools are displayed in a row on trolley tables beside the autopsy stands.

Just before the autopsy proper begins, the third series of photographs is taken, with the technicians, or the pathologist, recording any external injuries such as bruises, abrasions or compound fractures.

Gearóid Scully had several fracture injuries: his right femur (thighbone) and left tibia (shinbone) were broken, as was his first lumbar vertebra.

There was no injury to his head; the severe injuries, the wounds that ended his life, were all in his chest, Dr Bennani would discover.

The next part of an autopsy is what pathologists term an evisceration. A medic familiar with the progress of an autopsy explains. “We remove the sternum [the breast bone],” he says. They then remove the neck organs, lungs and heart. Next the intestines, stomach, liver, kidneys and spleen. Then the corpse is cleaned.

A pathologist is careful to access the brain in a way that leaves minimal visible evidence afterwards of the procedure that has taken place.

The organs are dissected and examined. Tiny biopsies – microscopic samples of tissue – are kept for histology, the study of tissue. When the autopsy is finished, the organs are returned to the body, sealed in bags.

“Then is we do the reconstruction,” explains a mortuary technician. “It’s sewn up neatly, with fine sutures; any cuts or abrasions are sutured, any protruding bones are sutured as well, and everything is wrapped . . . the body is washed down, hair dried.”

Not survivable

This was the procedure followed on January 1st last when Dr Bennani examined the body of Gearóid Scully in Mayo General.

He found that when the Skoda’s engine block was ripped from the car’s chassis and burst through the dashboard into Scully’s chest, it fractured his sternum, lacerating his heart’s left ventricle, the main chamber that pumps oxygenated arterial blood around the body.

The aorta, the main artery taking the rejuvenated blood from the left ventricle to the rest of the body (excluding the lungs) was also severely damaged. Dr Bennani would later describe Scully’s liver as having sustained “multiple fragmentations”.

Scully’s injuries were not survivable; they resulted in massive haemorrhaging and death would have been instant.

Dr Bennani followed normal procedures and sent samples of Scully’s blood and urine for testing in the State laboratories at Backweston Laboratory Campus in Celbridge, Co Kildare. The results showed no alcohol or other inhibiting or illegal substances were in his system at the time of death. Scully was 100 per cent clean.

The Atlas vertebra

In a road crash, there are usually three impacts, any one of which can kill. The first is when the vehicle hits an object – another vehicle, a wall, or a person perhaps. The second is when the driver, or other people inside the vehicle, hits the inside of the vehicle itself, or something inside the vehicle hits them, after the initial impact.

The third is when the internal organs of the people in the vehicle are jolted with such force, during either of the first two impacts, that the organs hit the inside of the person themselves and are damaged.

After doing the autopsy on Gearóid Scully, Dr Bennani called it a day. The next day, January 2nd, he returned to the morgue and conducted his autopsy on the body of Terence Beagan.

Beagan’s body showed evidence of fractures to both sides of his ribs and his sternum. But what killed Beagan, and killed him instantly, was what Bennani found at the base of his skull, where it is attached to the spine.

The saucer-like bone at the base of the skull is called the occipital bone. Below it is the spine.The uppermost bones of the spine are the seven cervical vertebrae. The Atlas vertebra holds up the skull. It is attached to the skull by the atlanto-occipital joint, which facilitates movement of the head.

This area of the skull and spine is critical to survival. The brain’s lines of communication with the heart pass through here. If the spinal cord is broken here, the heart stops and death is instant.

Dr Bennani found that Terence Beagan’s atlanto-occipital joint was dislocated, fracturing the Atlas vertebra and severing the spinal cord. As a result, there had also been a brain haemorrhage. The force of the impact had ruptured the cord and killed him instantly.

Dr Bennani also took blood and urine samples and sent them to the State lab for analysis.

These results would tell their own story.

Anatomy of a Car Crash: Part 4 - The verdict is published on Wednesday, December 10th, in The Irish Times and on irishtimes.com