Yesterday, armed police chased and shot dead a man at the Stockwell subway station in south London -- a shooting linked, they said, to their inquiries into the 21 July attacks.
The shooting was a watershed event in Britain, where only specialist officers carry weapons and killings by police are very rare.
Then, police released pictures of four men taken by transport-security cameras. The four are suspected of trying to detonate three bombs on the subway and one on a bus on 21 July.
Police say they're counting on the public to help them find Britain's most wanted men. "Anyone who has information about where these men currently are, you should immediately call 999 [emergency services] and ask for urgent police response. The public are asked not to approach them [the suspects], a police spokesman said."
Within hours, police said they had arrested a man in south London. Then, this morning, they announced another arrest -- both of them in the same area as yesterday's shooting.
Police won't say if the man killed or the men they arrested are among the four suspected bombers. What they are saying is that the attacks resembled the 7 July bombings, which also hit three subway trains and a bus.
But there's a big difference. On 21 July, the devices failed to go off properly, and no one was killed. More than 50 people died in the 7 July attacks.
The victims of those attacks continue to be buried. Today sees the funeral of a man who died on the bus, Anthony Fatayi-Williams.
His mother, Marie, made an emotional appeal for peace while her son was still missing: "Anyone who has been misled or is being misled to believe that by killing innocent people he or she is serving God is to think again, because it is not true. Terrorism is not the way, it is not the way, it does not beget peace."
After her son is buried, Fatayi-Williams says she plans to set up a peace and conflict-resolution foundation. It's a way to honor her son -- and make sure something good comes from the London attacks.
London Subway Shooting Comes As Terrorist Manhunt Continues
New London Explosions Follow Deadly Attacks By Two Weeks