For long periods, Florence Rey's features crease in puzzlement, as if she cannot recognise the events being described in the Paris Cour d'Assises; as if she cannot quite recall the other Florence Rey, who is on trial for murdering three policemen and a taxi driver, as well as 12 attempted murders, hostage-taking and robbery with violence.
All of this happened in the space of a crazy, murderous 25 minutes on the evening of 4 October 1994: an insane interlude in what had previously been - and what has since become again in prison - a studious, warm-hearted, self-effacing life. In prison, she writes poetry and plays; she is a model inmate; she helps to calm the wilder spirits among the other girls.
Ms Rey is now 23. An unflattering mugshot of her, issued by the police after her arrest, briefly turned her into a kind of folk-heroine among the disaffected element of French youth. She appeared on T-shirts and posters. She was one half of the "Bonnie and Clyde des banlieues [suburbs]"; a sallow, empty-eyed, courageous 19-year-old nihilist, who took on the "flics" and romantically lost.
Her boyfriend Audry Maupin, 23, died in her arms after leading her on a scatter-brained raid on a police car-pound in eastern Paris, which ended in a muddled and violent car chase into the Bois de Vincennes. (The two anarchist bandits had originally intended to go home by Metro.)
Their murderous escapade has been connected by some with Oliver Stone's 1994 movie Natural Born Killers, which tells the story of a pair of young psychopaths in the United States. A poster for the movie was found on the wall of the derelict house in which Maupin and Rey were squatting in Nanterre, west of the city.
However, their room was also full of "autonomist" (anarchist) and anti- police tracts, written by Maupin. There is no evidence that either of them saw Stone's movie before the fateful night.
Three policemen were shot dead at point-blank range. An African taxi- driver, who refused to co- operate and deliberately crashed his hijacked car into a police vehicle, was executed with a shot in the neck. All were murdered by Audry Maupin. No one suggests that Ms Rey killed anyone but she admits to firing several shots - 12 in all, says the prosecution - one of which hit a policeman who was already dying. She is charged with being a full participant in the murders.
Since her trial began last week, Ms Rey and her lawyer, Henri Leclerc, have tried to paint a picture of a confused, emotionally immature young woman, who wanted to prove herself to her domineering, fantasist boyfriend.
After meeting at university and sharing a love of rock-climbing, they dropped out of college together and lived an increasingly miserable existence, without water, electricity or money.
"By the end, I hadn't much I could say," she told the court. "I thought Audry had lost interest in me. I didn't know what to do. I was depressed. I just needed to show him that I was still there ... Mostly, I just didn't want to wait alone for him to come back."
On several occasions, Ms Rey has apologised, in tears, to the court and to the relatives of the four people who died. "I just want to say to the families of the victims that I am sorry," she said. "It was a terrible chain of events. I understand their grief. I know what it means to lose a friend, a father, a mother ... I just wish it hadn't happened."
But, little by little, this picture of Ms Rey - not an anarchist killer but an impressionable and troubled young woman, who joined the raid on the spur of the moment - has been shaken apart in court.
It was Ms Rey who bought the hooded anoraks and one of the hunting rifles used by the pair. Witnesses have described her as an active, cool participant in the robbery gone wrong. A second motorist, taken hostage after the death of the taxi driver, said she pointed a gun in his ribs and said: "If you stop, I'll plug you."
The motorist, Jackie Bensimmon, also claimed that she urged Maupin to shoot a pursuing police motorcyclist. "Go on, go on, plug him, what are you waiting for?" he reported her as saying. (Waking from her court reverie at this point, Ms Rey denied saying any such thing). According to Mr Bensimmon, when the young woman saw that the police had blocked the road ahead, she asked him, calmly: "Can you do a hand-brake turn, like in the movies?"
One remaining mystery in the affair is the role played by the second accused, Abdelhakim Dekar, known as Toumi. He is charged with being the lookout in the original raid. He denies (in the face of all the facts) ever having met Maupin and Rey and claims to be an undercover agent for the Algerian government.
Stephane Violet, a radical film-maker who briefly befriended the couple, told the court that he believed it was Dekar's taunting that pushed Maupin over the edge, from theoretical nihilism to an attack on the police pound.
And Ms Rey? "She rarely had anything to say. She was like a butterfly ... It was as if she wanted to be part of the conversation ... but couldn't really contribute anything."
Anarchist heroine; confused teenager; cool killer; repentant and intelligent young woman? The more the trial goes on, far from uncovering the real Ms Rey, the enigma grows.
Her mother, Anne Rey, clutching her daughter's excellent school reports, described a good-hearted, religious girl, who had never been in trouble until she met Maupin. "It's the story of a first love affair which went all wrong," she told the court.
The trial is expected to end next week. If convicted of murder, Ms Rey faces a life sentence.