A police colonel said black-clad kidnappers in several vehicles stopped his car and that his driver was wounded by gunfire when he tried to intervene.
An interior ministry official confirmed the kidnapping had taken place, without providing details.
A justice ministry official identified the man seized as Fares, saying he is also director general for financial and administrative affairs at the ministry.
The kidnapping came just four days after gunmen abducted 18 Turkish employees of a major construction firm in Sadr City, south of Binook.
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Kidnappings for political reasons or money are a persistent problem in Baghdad, with Shiite militias or their affiliates seen as the main culprits.
Baghdad turned to mostly Shiite volunteer forces for support as the Islamic State group advanced towards the capital in June last year, and they have played a key role in halting and then reversing the jihadists' gains.
But in doing so, the government also further empowered Shiite militias, some with chequered human rights records, and spurred the creation of new ones, allowing them to act with near impunity despite their officially falling under government command.