The former German Federal Minister of the Interior Hans-Peter Friedrich told Der Spiegel that surveillance cameras are effective in stopping suicide bombers . . .
[Translation]: DER SPIEGEL: Widespread video surveillance in the US could not prevent [the Boston Marathon] attacks. Rather, the perpetrators seem to have been fully aware of the monitoring.
Friedrich: A suicide bomber, who includes his own death in his planning of the attack won't be discouraged by surveillance cameras.
DER SPIEGEL: So the cameras are ineffective?
Friedrich: That'd be a wrong conclusion. If we catch the attacker after the first time, he can't act a second or third time. That alone is already a success.
[Hat tip Felix Mueller]