The gunman who killed seven people in south-west France in a series of shootings sent a video of the murders to media before being shot dead by police.
Mohammed Merah killed three soldiers, three children and a rabbi in three incidents over ten days near Toulouse.
According to witnesses to Merah's attack on a Jewish school, the gunman recorded the murders via a video camera hung around his neck.
He also boasted about filming the killings during the armed stand-off with police.
That footage was subsequently sent to the Al Jazeera, who passed it on to the French authorities.
The broadcaster said it received a memory stick with clips from the killings set to music, alongside readings from the Koran.
The package was reportedly dated 21 March, leading police to suspect it was sent by a third party after police surrounded Merah's flat.
"Investigators are trying to find out whether the letter was posted Tuesday night by Mohamed Merah himself or by an accomplice Wednesday morning," said the French newspaper Le Parsien.
Merah's brother was reportedly been charged with complicity in the killings.
Meanwhile Merah's father said he would sue the French government over his son's death, saying that "France is a big country that had the means to take my son alive".
Police investigations have focused on how Merah was able to acquire an arsenal of guns including an Uzi sub-machinegun, while apparently having little income and being under watch by the French authorities.
During the dramatic raid that led to his death on Thursday morning, Merah shot at police more than 30 times. Prosecutors said they did "everything we could" to arrest him alive.
"We had to get him in the end. What else can we tell you," prosecutor Francois Molins said during a press conference.
Prosecutors have confirmed Merah was the gunman behind the three attacks that killed seven people in the region and had a stash of weapons.
Molins also confirmed that Merah filmed all three of his killings, including the murder of a three soldiers and the killing of four people at a Jewish school.
They said five police officers were injured in the operation. Prosecutors added that the 23-year-old may have become radicalised in prison, telling journalists that although he was known as a petty criminal "it was during his time in prison that he decided to read the Koran".