The Ahmedabad police on Saturday arrested seven persons in connection with the November 5 murder of Congress worker and RTI activist Nadeem Sayed, a key witness in the case of Naroda-Patiya massacre during the 2002 Gujarat riots. Among the seven was Kalu Gardan, who, it was claimed, knifed Nadeem when he just came out of his Juhapura residence. While the motive behind the murder was still not known, the police earlier detained a local builder, Mehboob senior, after it was revealed that he had been issuing threats to Nadeem, warning him not to appear as a witness in the Naroda-Patiya case.