Alam gave his confession before crime branch sleuths and confirmed it before a magistrate Tuesday, police sources said.
The magistrate would send Alam's confession in a sealed cover to MCOCA court hearing the case.
Alam arrested a fortnight ago is accused of acting as a conduit between Salem and the killers of Dewani.
Earlier, Salem also confessed his role in the killing by making a confession before police and confirming it before the magistrate.
Dewani was murdered in 2001 allegedly by Salem's men as he refused to pay the extortion money.
