When the experts go astray: a denial of justice for Michael Lognonne

The order handed down by the Paris Court of Appeal on 24 January 2025 brought to a close a judicial investigation that had lasted six years. In the Jérôme Rodrigues case, the judges ordered police officer Brice C. to stand trial before a criminal court (cour criminelle) for assault resulting in mutilation. On 26 January 2019, during Act XI of the Yellow Vest protests on Place de la Bastille, this officer from the CSI, one of the police’s intervention units, had thrown a sting-ball grenade (GMD) into the middle of a group of protesters gathered beneath the July Column. One of the grenade’s eighteen projectiles struck Jérôme Rodrigues in the face, causing the permanent loss of his right eye.

In the same order, the Court of Appeal dismissed the case over the injury suffered by a second protester, Michael Lognonne, who had also filed a complaint. He was standing right next to Jérôme Rodrigues when the grenade exploded, and several videos of the scene show him collapsing to the ground moments later. Wounded in the right leg, he told Index in March 2025: “I still have problems with my wound, it makes me limp, it starts bleeding again… I’m 45 and I limp – when I’m 75, what am I going to do?”

To determine the origin of Michael Lognonne’s injury, the investigating judges commissioned a medical and ballistic expert report. Based on their reading of the marks on his leg, the experts concluded that “only the 40 mm LBD was capable of causing an injury of the appearance observed”. But as no such LBD shot could be identified, the same experts, joined by a third, found that “the images did not make it possible to explain when and how Michael LOGNONNE had been wounded in the leg”. For lack of evidence, the judges dismissed the case.

When this decision was announced, Index, which had already produced a detailed reconstruction of the circumstances of Jérôme Rodrigues’s injury, resumed its analysis of the available footage. Against the conclusions of the court-ordered expert reports, its counter-investigation, presented in the video above, clearly establishes how Michael Lognonne was wounded.

The available footage shows that Michael Lognonne was about two metres from the GMD grenade thrown by officer Brice C. when it exploded.

A sting-ball grenade contains 18 rubber pellets which, on detonation, are projected in all directions at an initial velocity of between 400 and 500 km/h. Anyone within 15 metres of the blast can be struck with great force by these projectiles. Michael Lognonne’s position is therefore entirely consistent with an injury caused by this grenade.

One second after the explosion, an LBD shot was fired by a police officer identified as Baptiste R. This shot is visible from several angles in the available videos. Drawing on these images, Index produced a 3D model of the scene, incorporating the shooter’s position and the direction his weapon was pointing when he fired. This reconstruction shows that the projectile passed well clear of the group Michael Lognonne was standing in. Baptiste R.’s LBD shot therefore cannot have caused his injury.

The possibility of a second LBD shot was raised during the proceedings. Yet audio and video analysis of all the available sources clearly shows that only one LBD shot was fired nearby in the window during which Michael Lognonne was wounded: Baptiste R.’s, which, as shown above, cannot have hit him.

Between the last moment Michael Lognonne is seen on his feet and the moment he collapses, only one event capable of causing his injury occurs: a sting-ball grenade exploding at his feet. Index can therefore say that Michael Lognonne was wounded by the grenade thrown by officer Brice C. – the same one that cost Jérôme Rodrigues his eye.

Index’s counter-investigation also exposes the flaws in the judicial proceedings in Michael Lognonne’s case, which gave decisive weight to expert reports of questionable methodological rigour.

In January 2020, a first “forensic medical and ballistic expert report” was submitted to the investigating judges in charge of the Rodrigues/Lognonne case. It is signed by Pierre Laurent, an expert in “weapons, ammunition, ballistics, and pyrotechnics” – who is regularly appointed in the police violence cases Index has studied – and Dr Frank Questel, an expert in “forensic medicine, toxicology, and bodily injury”. In this report, the experts state with certainty that Michael Lognonne’s injury was caused by an LBD shot. In doing so, they rule out just as categorically the possibility that it was caused by a GMD grenade exploding, despite a whole series of items in the case file – videos, witness statements, medical examinations – pointing to precisely that.

To justify their opinion, the two experts rely on an examination of Michael Lognonne’s injury carried out at the hospital on 20 September 2019 – almost seven months after the events.

In their medical and ballistic summary, the two experts write:

Examination of the procedural documents and videos confirms that at the moment when Mr LOGNONE and Mr RODRIGUES were injured, a sting-ball grenade had been thrown in their direction and that a 40 mm LBD round had been fired one second after the grenade exploded, again in their direction.

A first error – a major one, given the task they had been given – can be identified here. From a superficial reading of the available videos, the experts take it that the LBD shot fired by Baptiste R., discussed above, was aimed at the group where Michael Lognonne and Jérôme Rodrigues were standing. Yet the 3D reconstruction clearly shows that it was not, and that it could not have hit Michael Lognonne.

To illustrate their analysis, the experts provide the following reconstruction diagram, in which the LBD shot is represented by a green arrow, wrongly pointed towards the group of protes

The summary continues:

Of these two weapons, only the 40 mm LBD was capable of causing an injury of the appearance observed. Indeed, the size and the “ring-shaped” appearance of the scar is typical of a non-penetrating impact by a soft, high-energy, large-diameter projectile, namely [….] a 40 mm LBD projectile. An impact by a GMD pellet would have left a smaller mark, without the “ring-shaped” appearance.

On the shape of the injury alone – which they read as “ring-shaped” – the experts settle the question of which weapon caused it. To justify this, they rely on a speculative reading of its shape and put forward a flawed argument.

On the shape of the injury, the experts ignored the opinion of Dr Lormeau, of the Paris forensic medical unit, who, having examined Michael Lognonne on 12 February 2019, 17 days after the events, described his injury as follows in his medical certificate:

On the anterior aspect of the middle portion of the leg, a horizontal wound in the process of healing, with a fibrinous base, measuring 1.7 cm × 0.7 cm, surmounted by a healed, erythematous wound of rectangular shape with a long axis of 2.5 cm.

Commenting on a photograph of the injury taken the day after the events, presented by Mr Lognonne, the same Dr Lormeau describes it as “a wound of contused appearance, of overall shap

A sting-ball grenade pellet is rectangular with rounded edges, measuring 2.8 × 2.2 cm. Its shape and dimensions are therefore entirely consistent with “a wound […] of rectangular shape with a long axis of 2.5 cm”, as recorded by a doctor in a medical certificate that is in the case file – and that is even cited, though disregarded, in Mr Pierre Laurent and Mr Franck Questel’s expert report.

Index also tested the experts’ claim that “an impact by a GMD pellet would have left a smaller mark, without the ‘ring-shaped’ appearance” against a sample of images of injuries caused by GMD grenades, drawn from the database of the website violencespolicieres.fr. They show injuries of widely varying shapes, several of them circular. Some of these wounds and marks on the skin are as large as Michael Lognonne’s, or larger. These examples therefore contradict the experts’ claim about the characteristic size and shape of injuries caused by sting-ball grenades.

To explore this question further, Index sought the opinion of two other doctors, Dr Abdelrani Bourazi and Dr Marie Nemon, who recorded their analysis in a medical certificate. In their view, from observation of Michael Lognonne’s injury alone, “it is impossible to rule out the hypothesis of an injury caused by a sting-ball grenade.”

Given everything that contradicts it, it appears that the authors of the forensic medical and ballistic report, Mr Pierre Laurent and Mr Frank Questel, made an expert error: the appearance of the injury in no way establishes that Michael Lognonne was wounded by a 40 mm LBD projectile.

In April 2022, the judge in charge of the judicial investigation appointed Mr Philippe Esperança, a forensic science expert, to analyse the available videos of the incident and “produce a 3D model of the sequence of events.” The expert submitted his report in July 2022.

As regards the LBD shot fired by Baptiste R., the 3D reconstruction produced by Mr Esperança matches Index’s. At the end of his report, the expert concludes that “the LBD shot does not appear to hit either of the two victims” and that “the GMD throw is the cause of Mr Jérôme RODRIGUES’s injury and in all likelihood of Mr Michael LOGNONNE’s.”

Faced with the conflicting conclusions of the expert reports in the case file, the investigating judges ordered the authors of the medical and ballistic expert report and the author of the forensic science expert report to produce a “supplementary joint summary […] so that they may compare their reasoning and conclusions.”

In their joint report, submitted on 15 June 2023, the authors of the medical and ballistic report stood their ground, confirming that Michael Lognonne’s injury resulted from a 40 mm LBD shot and that the GMD grenade could not have caused it.

The forensic science expert likewise maintained his conclusion regarding the LBD shot fired by Baptiste R., which could not have reached Michael Lognonne given its direction and the shooter’s position. He also noted that when the shot was fired, colleagues of Baptiste R. were standing between him and Michael Lognonne – a point Index’s 3D reconstruction also confirms.

Having failed to resolve the contradiction between the earlier reports, the joint summary ends without a conclusion – from which the investigating judges took it that “the images studied did not make it possible to establish when and how Michael Lognonne had been wounded in the leg.”

In their order dismissing the case over Michael Lognonne’s injury, the investigating judges once again cite the first forensic medical and ballistic report, holding that “it is ultimately taken as established that Michael Logonne was struck on the right shin by an LBD shot.”

The judges also regard the forensic science expert’s conclusions as “categorical”: the trajectory of the LBD shot fired by Baptiste R. was not directed towards Michael Lognonne and therefore could not have hit him.

Having failed to establish how Michael Lognonne was wounded, the proceedings – which nonetheless lasted six years and involved three experts and as many expert reports – thus ended with the abandonment of the prosecution for “violence with a weapon by a person vested with public authority” in relation to his injury. And the judges concluded: “We find that there are, as matters stand, no grounds to proceed against [Baptiste R.] or against anyone else on this count.”

Index’s counter-expertise establishes that Michael Lognonne was indeed wounded by the same GMD grenade that blinded Jérôme Rodrigues in one eye – not only the most plausible cause of his injury, but the only possible one.

It has also identified the medical and ballistic expert error that led the proceedings into a dead end: the claim by experts Pierre Laurent and Franck Questel that the shape of the injury categorically rules out a sting-ball grenade rests on nothing more than an argument from authority; it is contradicted by several comparable documented injuries and by the opinion of two other doctors. In the interest of establishing the truth, Index is publishing the conclusions of its independent counter-expertise, so that the courts may act on them.

Finally, the facts bear restating: a single sting-ball grenade thrown into a group of protesters left two people with permanent injuries, neither of whom was found to have committed any offence. This finding underscores, once again, the inherent danger of these weapons, which remain officially classified as “war materiel.” Despite dozens of documented cases of people seriously injured by them, sting-ball grenades remain part of the police arsenal in France and are still regularly used by the police and gendarmerie, including outside public order operations.