The body of 14-year-old Alice Gross was found in a river in west London on Tuesday. She had been missing since August 28 and was last seen walking along a canal towpath nearby.
The main suspect in the case is Arnis Zalkalns, 41, who served seven years in prison in Latvia for stabbing his wife to death.
Police have yet to confirm that the body is that of Zalkalns, who was last seen on September 3, but several British newspapers reported that it was.
The search for the schoolgirl was the biggest police operation in London since a series of suicide bomb attacks hit the capital in 2005, killing 52 people.
Prime Minister David Cameron said Friday he would "examine all the circumstances" surrounding the murder to see if lessons could be learnt.