Sept. 26, 2014: ISIS Lieutenant Tries to Coordinate Attacks in Australia

A 22-year-old Sydney man was allegeldy asked by an Islamic State lieutenant to carry out a beheading in Australia on camera, the police said.

Days after that Sydney man was arrested, an 18-year-old man stabbed two counterterrorism officers outside Melbourne before one of the officers shot and killed him. The police described the man as a “known terror suspect” who had been seen carrying an Islamic State flag at a local shopping center.

May 24, 2014: 3 Shot Dead at Jewish Museum in Brussels

French authorities arrested Mehdi Nemmouche, a 29-year-old Frenchman with a long criminal history who had traveled to Syria last year to join radical Islamist fighters there.

French and Belgian officials said evidence linked Mr. Nemmouche to the Islamic State, and a French journalist held hostage in Syria in 2013 identified Mr. Nemmouche as one of his captors.

European officials said that the Brussels killings appeared to be the first committed in Europe by a European citizen returning from Syria.

May 22, 2013: Attack Near Military Barracks in South London

Image A video image of one of the two men the authorities said carried out an attack last year in south London, near the headquarters of the Royal Artillery. Credit... The Sun, via Agence France-Presse — Getty Images

Two British-born converts to Islam were found guilty of murdering a British soldier, who was run over with a car on a southeast London street and then hacked with knives and a meat cleaver as closed-circuit cameras recorded parts of the grisly scene.