CAIRO — Egyptian authorities produced on Thursday what they said was a confession by the son of a top member of the Muslim Brotherhood, trying to bolster accusations that the Islamist group has linked to al Qaeda-inspired militants who have claimed deadly attacks on police and other targets in recent months.

The county’s Interior Minister aired the recording said to be a young Yahia Mongi, son of a Brotherhood lawmaker, in which he says he joined the Ansar Beit al-Maqdis or Champions of Jerusalem group that claimed responsibility for a suicide bombing of a police station last month.