Mother deepti chawla killed Sarthak in Ghaziabad?

Who killed Arushi?Father was suspected but there is no clue as to what really happened.
Recently Doctor mother deepti chawla is suspected to have killed her 4 yer old son Sarthak Chawla.She is under treatment and has to undergo a polygraphic or narco test.
He was hammerd till death.And the house was locked from inside .the incident took place on 5th of feb 2009.
Father Rajesh Chawla is also a homeopathic doctor.
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