Updated at 5:30 p.m. ET
The man who is believed to have carried out a deadly attack near the U.K. Parliament has been identified by Britain's Metropolitan Police as Khalid Masood, 52.
Police believe the man acted alone. He was shot and killed after carrying out an attack that killed a police officer and three civilians and wounded several others around 2:40 p.m. local time Wednesday. (Two of the civilian victims died on Wednesday; the third was hospitalized after the attack and died Thursday.)