Timeline: UK ricin terror probe
LONDON, England (CNN) -- Here is a timeline of events in the investigation into an alleged terror plot involving the deadly poison ricin in Britain:
Sunday January 5
• British police raid two addresses in north and east London and discover traces of ricin, one of the world's deadliest poisons. Six men of Algerian origin are arrested, as is a woman who is later released.
• French intelligence services provided the tip that led British authorities to make the arrests, sources tell CNN.
• Sources tell CNN the suspects have been in Britain no more than three months. Two of them are asylum-seekers living in government housing.
Tuesday January 7
• Anti-terrorism police investigating the ricin discovery in London arrest a seventh man, aged 33, and hold him at a London police station.
Friday January 10
• The FBI advises U.S. law enforcement agencies about the dangers associated with ricin following the discovery of the deadly poison in London. The FBI notice says ricin "could be used in a terrorist operation to contaminate closed ventilation systems ... drinking water, lakes, rivers and food supplies."
Saturday January 11
• Four of the seven men arrested in connection with the ricin investigation are charged with terrorism offences, Scotland Yard tells CNN. The four are charged with "possession of articles of value to a terrorist" under the Terrorist Act 2000 and with "being concerned in the development or production of chemical weapons" under the Chemical Weapons Act 1996.
Sunday January 12
• Anti-terrorism police arrest five men and a woman in Bournemouth, on England's south coast, in connection with the London ricin discovery. Police refuse to confirm the arrests are connected to the ricin discovery, but sources admit privately to CNN the arrests are linked. Officers search two premises in the Bournemouth area; no chemical materials are found.
Monday January 13
• Four men charged with terrorism offences in connection with the ricin discovery appear at Bow Street Magistrates' Court in central London and are remanded in custody. Three of them are named as Mouloud Feddag, Samir Feddag and Mustapha Taleb. The fourth is a 17-year-old who can not be named for legal reasons.
Tuesday January 14
• A police officer is killed and four others are wounded during a raid in Manchester, England, into the alleged ricin terror plot. Detective Constable Stephen Oake is stabbed to death as police arrest three men -- all described as north Africans -- in the northern England city.
Thursday January 23
• A 31-year-old north African man is arrested by police investigating the January 5 discovery of ricin in north London.