Boston bombings: Cops take suspect into custody

Investigators have arrested a suspect in relation to Monday's Boston marathon bombings, law enforcement officials have said. The breakthrough reportedly came from security video of a man dropping off a bag on the street near the race's finish line, before walking away.A The twin blasts killed an eight-year-old boy, a woman aged 29 and a postgraduate student from China. Officials are due to hold a press conference at 17:00 ET (21:00 GMT).

Investigators have been sifting through thousands of pieces of evidence, ranging from video recorded on mobile phones to fragments of shrapnel removed from the victims' legs. More than 170 people were wounded in the attack. The image of the suspect came from surveillance video recorded at a department store across the street from the site of the second blast, CNN reported. The Boston Globe newspaper reported that a surveillance camera at the Lord & Taylor store had provided police with clear footage of the area.

Earlier, the Associated Press quoted a source close to the investigation as saying that the bombs consisted of explosives placed in 1.6-gallon (6-litre) pressure cookers, one with shards of metal and ball bearings, the other with nails.

Nobody has claimed responsibility for the bombs, which a source said were placed in black bags and left on the ground. It has been reported that a circuit board and battery pack - parts of a triggering mechanism - were recovered. And the lid of a pressure cooker, apparently blown off during the explosion, was found on the roof of a nearby building, an official said on Wednesday. (BBC)