Prosecutors in Belarus have released images said to show a person planting a bomb that killed 12 people and injured 200 on the metro in the capital, Minsk.
One image shows what appears to be a man carrying a hold-all in the central aisle of a metro station as people board a train beside him.
The time shown is nearly 1744 (1444 GMT) - 12 minutes before the blast.
Three more arrests have been made, bringing the total to five, while no motive has yet been forwarded.
Deputy Prosecutor General Andrei Shved said on Thursday that the five, including the suspected bomber himself, were Belarusians under the age of 30, and another official reportedly added that one of them was a woman.
"The perpetrator [of the attack] has been found," Mr Shved told reporters in Minsk.
"Some of his accomplices have been identified."
Earlier, Belarus's authoritarian President, Alexander Lukashenko, announced that two of the detainees had confessed to the attack.
Oleg Voronin, an official at the prosecutor general's office, told Russia's Ria-Novosti news agency that one of the detainees was a woman.
The exploding bomb showered rush hour commuters at the Oktyabrskaya metro station with nails and ball bearings.
Terrorist attacks are almost unheard-of in Belarus, where the authorities have been widely accused of seeking to stifle political opposition to Mr Lukashenko, in power since 1994.
Mr Lukashenko said the suspects arrested earlier were linked to two previous bombings - one in Minsk in 2008 and one in the eastern city of Vitebsk in 2005 - in which some 50 people were injured.