Mau Mau Uprising attempt to eliminate Mau Mau's presence within Nairobi in one fell swoop. 25,000 members of British security forces under the control of General George Erskine were deployed as Nairobi was sealed off and underwent a sector-by-sector purge. All native Kenyans were taken to temporary barbed-wire enclosures, whereafter those who were not Kikuyu, Embu or Meru were released; those who were remained in detention for screening. Whilst the operation itself was conducted by Europeans, most suspected members of Mau Mau were picked out of groups of the Kikuyu-Embu-Meru detainees by a native Kenyan informer. Male suspects were then taken off for
Mau Mau Uprising son—who, after confessing, joined screeners at Athi River Camp, later travelling throughout the Pipeline to assist in interrogations. Suspected informers and spies within a camp were treated in the time-honoured Mau Mau fashion: the preferred method of execution was strangulation then mutilation: "It was just like in the days before our detention", explained one Mau Mau member later. "We did not have our own jails to hold an informant in, so we would strangle him and then cut his tongue out." The end of 1955 also saw screeners being given a freer hand in interrogation, and harsher conditions than straightforward