The German Chaos Computer Club has uncovered two recent instances of police using trojan spying programs on the computers of suspects they later arrested. The programs allowed remote users to take over webcams, listen in on internet phone calls and take screenshots every 30 seconds.
All that would exceed the laws currently on the books in Germany, which only allow authorities to tap computers for phone calls.
Interior Minister Hans-Peter Friedrich said the government would re-examine the software it was using but that internet telephone monitoring would continue.
Al Jazeera's Nick Spicer reports from Berlin.
