The CIA has confirmed it wanted one of the Boston bombing suspects placed on a terrorist database 18 months ago.

The agency had the elder brother, Tamerlan Tsarnev, added to the TIDE database after Russian authorities raised concerns about his activities and alerted their US counterparts.

19 year old Dzhokhar Tsarnaev and his brother 26 year old Tamerlan were identified as the main suspects in the bombing of the Boston marathon.

Three people were killed and more than 170 others injured when two bombs exploded at the finish line of the marathon on Monday last.

Last Friday night saw the town of Waterown in Massechussetts go into lockdown as police tried to capture the two brothers. Tamerlan and a police officer were killed during a shootout between officers and the pair.

A memorial service was held for the police officer killed in a shootout during the search for the two men.

His brother Rob Rogers paid tribute.