SIM cards used in underage prostitution

October 5, 2013
The Yomiuri Shimbun
Two men recently who were arrested by the Metropolitan Police Department on suspicion of prostituting high school girls switched the subscriber identity module (SIM) cards in their smartphones with those used only for data communications to hide their identities, according to investigation sources.

A SIM card is a tiny card containing an integrated circuit chip. It is used to record information about the subscriber of a mobile phone or the user of a tablet computer or smartphone, including a telephone number and an e-mail address.

SIM cards equipped only with data-communication functions do not require identification of the buyer, whereas purchasers of regular SIM cards are obliged by law to provide identification. With regular SIM cards, holders of cell phones, including smartphones, can use both data communications and voice calling functions. However, smartphone users can use voice calling apps if they know the other party’s user ID.

The MPD arrested the two men, one of them a 51-year-old unemployed man of Tokorozawa, Saitama Prefecture, on suspicion of violating the Anti-Prostitution Law, alleging that they introduced underage girls as prostitutes using applications that allow users to make phone calls free of charge. The police said the two men changed their smartphone SIM cards with those used only for data communications to prevent their identities from being discovered by police.

The number of female minors involved in criminal cases using free call applications has been increasing, according to the MPD. It has asked cell phone dealers to voluntarily take steps to confirm the identities of purchasers, as the use of SIM cards for data communications for criminal purposes is expected to continue.

Smartphones are usually equipped with standard SIM cards that enable both voice calling and data communication functions. However, with data communications-only SIM cards, users can only send e-mails and use the Internet. As a result, many of the cards are used with tablet terminals and smartphones as an alternative to personal computers, according to industry sources. Data communication charges are lower for such SIM cards.

According to a senior MPD official, the two men, arrested in June and already indicted, are on trial on suspicion of violating the Law on Punishment of Activities Relating to Child Prostitution and Child Pornography, and the Protection of Children.

They bought several data commu-nications-only SIM cards, which do not require subscriber identification at the time of purchase.

They exchanged the original SIM cards with the cards in question in their smartphones and downloaded free voice calling applications such as Line and Kakao Talk. Then they posted messages such as “We’ll introduce girls to you” to solicit customers on online bulletin boards reserved for exchanging user IDs. They used similar methods to lure women, including high school students. With such apps, users can exchange messages if they know another’s user ID, even if they do not know the user’s smartphone telephone number or e-mail address.

The two men abused the function. For about seven months from November last year, the two men introduced about 10 female minors to several dozen men and received a total of about ¥15 million in commissions, the sources said.

The law to prevent improper use of cell phones obliges mobile retailers and related business operators to confirm whether the purchaser and the subscriber are the same person when they sell cell phones, smartphones or standard SIM cards. But data communications-only cards are not covered by the rule.

The unemployed man previously worked for an information technology company. An investigative source quoted him as telling the MPD, “Because holders of data communications-only cards are not identified, I thought whatever we did, our identities would not be revealed.”

But when he posted messages on the bulletin board, he erroneously used his smartphone with the original SIM card, not a data communications-only SIM card. Thus the MPD discovered his identity, the sources explained.

The men bought the data commu- nications-only SIM cards online. The MPD asked four companies, including the telecommunication firms that sold the cards to the men, to voluntarily confirm purchasers’ identities by, for instance, asking customers to send copies of identification documents at the time of purchase. The MPD also asked companies operating the free voice calling apps to take measures against possible abuse of the software.

According to the National Police Agency, in the first half of this year, 117 students under 18 became victims of sex-related crimes after disclosing their user IDs for free voice calling apps on online bulletin boards, a jump from 36 for all of last year.

Line Corp., the operator of Line, has changed settings so that minors who use certain phone models cannot exchange messages or make phone calls only with Line user IDs.

The demand for data communi- cations-only SIM cards has been rapidly rising, as more people have been using different types of mobile devices for different purposes. For example, some people use conventional mobile phones for making phone calls and smartphones for e-mail and the Internet. In 2008, the law to prevent improper use of cell phones obliged retailers to verify purchasers’ identities when they sell standard SIM cards. But data communi-cations-only SIM cards were exempted from the regulation.

An official of the Internal Affairs and Communications Ministry said, “Because they [data communications-only SIM cards] do not have voice calling functions, we did not anticipate that they would be used in crimes.”

However, the emergence of free voice calling apps for smartphones has made it possible to download the software with data communications-only SIM cards and to make phone calls with the apps.

The senior MPD official added: “Due to technological advances, data com- munications-only SIM cards now have almost the same functions as standard SIM cards. We need to make verification of purchasers’ identities a requirement immediately.”

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