"We have detained his wife Pramila and interrogating her to find out the whereabouts of Kasawa," District Superintendent of Police, GG Pandey told PTI.
Kasawa, who carries a reward of Rs 1 lakh on his head has been absconding since the blast on Saturday.
According to Seema Alawa, District Additional Superintendent of Police (ASP) and head of SIT, formed to arrest Kasawa, some other family members of the accused have been detained. (But) "I won't disclose their names," she said adding search operations have been intensified to nab him.
The explosion occurred in Kasawa's building with the accused said to possess a licence for use of explosive material in the digging of wells.
According to police, he had stored the explosive material, including gelatin sticks in huge quantity, in the residential building which also housed two shops and was situated close to the busy Sethia Restaurant in the new bus stand area.
A top official associated with the probe had said that Kasawa's mobile phone was functioning till Saturday afternoon (even after the explosion) and his family members had been contacted using that phone.
Meanwhile, politics over Kasawa thickened here, with Congress leader and former Union Minister Kantilal Bhuria staging a protest at city Kotwali Police Station demanding that state BJP chief Nandkumar Singh Chauhan should be booked immediately.
"Nandkumar has told media in Bhopal that Kasawa was a close friend of my son Dr Vikrant which is totally baseless. My son does have a friend whose name is Rajendra Kasawa but he is 30 and lives in Jhabua town not in Petlawad," Bhuria said.
