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@Bjinse: Some court cases have been won by default where wire taps played a role. Dutch police can't delete wire taps of lawyer/client conversations because the system is bought from Verint (Israel) and the company won't allow entry by "third"parties. See a partial reposting of my 2010 diary ...

Justice minstry Internet taps up five fold in one year

(Dutch News) July 19, 2013 - The number of Internet taps carried out by Dutch police rose 500% to 16,600 last year, according to new justice ministry figures. By contrast, the number of phone taps rose just 3% to nearly 25,500 despite doubts about their usefulness. And the number of requests for information about phone calls - such as the location calls were made from - reached almost 57,000, up 10% on 2011. The Netherlands sanctions more phone taps than any other country in the world. The figures do not include taps by the security services.

My dairy @BooMan - Dutch Are Champions with 26,435 Phone Taps [January 10, 2010]

Dutch intercept recordings done by Israeli supplier Verint ...

Phone taps, Justice and intelligence services

(BBC News) - The Dutch have been using telephone tap evidence since the 1970s - anyone who is suspected of having committed a crime punishable with four or more years in prison can be the subject of a telephone intercept.

Once Dutch police officers have a warrant from a judge they tell the telephone service providers to divert all calls via a central intercept centre. The calls are recorded digitally and the police computer can store as many as 10 million calls.

Safeguards

Robert Van Bosbeek, the Dutch police commissioner in charge of this operation, stresses that ordinary police officers are not allowed access to the area where the recordings are made in order to preserve the integrity of the recordings.

All calls are recorded so that they can also provide material for the defence. However, there are some concerns from the Dutch data protection authorities about the recording of calls between lawyers and their clients.

Dutch Police Don't Know How to Delete Intercepted Calls

"The law in the Netherlands says that intercepted phone calls between attorneys and their clients must be destroyed. But the Dutch government has been keeping under wraps for years that no one has the foggiest clue how to delete them (Google translation). Now, an email (PDF) from the National Police Services Agency (KLPD) has surfaced, revealing that the working of the technology in question is a NetApp trade secret. The Dutch police are now trying to get their Israeli supplier Verint to tell them how to delete tapped calls and comply with the law. Meanwhile, attorneys in the Netherlands remain afraid to use their phones."

Dutch article NRC newspaper: Ministry of Justice had no knowledge how to delete wiretaps

See e-mail from an expert of the Korps Landelijke Politiediensten (KLPD) establishing the fact the technology is proprietary of the Israeli supplier of the computersystem for intercepts (Verint).

"It is explained to me by representatives of the head company that information is deleted in one of the subsystems of the interceptsystem. This subsystem is named "Netapp" and is obtained by our supplier from their supplier of this subsystem."