Images recently appeared on the social network site Twitter claiming to show an adult Jon Venables, who was released from jail on licence with a new identity in 2001.
The Attorney General said court papers will be served shortly to bring contempt proceedings against those who posted the pictures, which have since been taken down.
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In a wide-ranging Peston on Sunday interview, he said Parliament security needs reviewing and the PM's counter-terror strategy is flawed.
The star celebrated his 70th birthday with his family before attending a celebrity-filled bash held in his honour.
Douglas Carswell told ITV's Peston On Sunday he wanted to "support" the government as a "critical friend" but refused to rule out a return.