Why this farce of arrests?

Sagar Sarwar and Mehrun Runi were brutally murdered on February 11, 2012 in their apartment in West Rajabazar in front of their son Megh. During the last one year, the police failed to shed any light on the horrifying incident. DNA samples of some professional thieves were sent abroad and the mortal remains of Sagar-Runi were exhumed from their graves for forensic test. It was very painful for their relatives. But the mystery remained as it was.
From the February 10, 2013 issue of The Daily Star, we learned that security guard Enamul was arrested by RAB on February 9, 2013. We are very surprised by this news because Enamul had earlier been arrested several times and police had to let him go as they could not find any evidence against him.
On October 10, 2012 Home Minister Mohiuddin Khan Alamgir claimed to have identified seven suspects including Enamul and announced a bounty of Tk 10 lakh on Enamul. So, Enamul was arrested and brought to the RAB headquarters for questioning.
Megh, son of Sagar-Runi, was interrogated by the police and RAB, but he did not mention the name of Enamul. It is hard to understand why he was arrested. I have to quote a few lines from Rabrindranath Tagore's dance drama "Shyama": "Chor chai, je korei hok, hok na she je kono lok."