Britain has opened an inquiry into the 2005 suicide bombings on London's transit system by releasing new details about the bombers and the initial confused response of authorities to the attacks.
The inquiry began Monday in a London court with a reading of the names of the 52 people killed in the bombings on three underground trains and a bus during the morning rush hour on July 7, 2005. Court officials and relatives of the victims also observed a minute's silence.
Four British Muslims carried out the attacks, the country's worst-ever in peacetime. Attorney Hugo Keith told the court the bombings were acts of "merciless savagery" that underline the "sheer inhumanity" of the perpetrators, as he put it.
He said evidence retrieved from the lead bomber's mobile phone suggests they may have planned to strike the day before.
Keith said lead bomber Mohammed Siddique Khan sent a text message to another attacker at 4:35 a.m. on July 6 calling off a planned rendezvous due to a "major problem."
He also said travelers reported seeing the four bombers smiling, laughing and generally relaxed on the morning of July 7 as the group took a train to London carrying backpacks filled with explosives.
Keith said the backpacks contained improvised bombs that could be thrown, indicating the attackers were prepared to fight police if intercepted.
The court heard recordings of phone calls between London underground staff and emergency services in the minutes after the bombers attacked three separate trains at 8:50 a.m.
The recordings showed authorities initially were confused about the cause of the incidents, attributing one to an electrical problem and another to a train derailing and hitting a wall.
Presiding judge Heather Hallett said she will try to determine whether British intelligence services could have prevented the bombings, as some of the victims' relatives believe. The inquiry is expected to last five months.
Some information for this report was provided by AP.