Officers and investigators found the body in west London, less than a week after confirming that they had found the remains of schoolgirl Alice Gross.
BBC QUESTION TIME APOLOGISES TO ALICE GROSS'S FAMILY FOR 'INSENSITIVE' COMMENTS
Zalkalns, 41, was named as the prime suspect after he was caught on CCTV cycling behind Alice Gross.
The footage was the last time the 14-year-old was seen alive.
Alice was reported missing on the 28th of August, but before the discovery of her body the teenagers family were clinging onto the hope that their daughter would be found safe and well.
ALICE GROSS POST-MORTEM PROVES INCONCLUSIVE
Latvian-born Zalkalns was previously jailed for seven years after he confessed to murdering his wife.
He then moved to the UK where authorities were unaware of his previous convictions.
Police have yet to confirm if the body found is that of Arnis Zalkalns.