Sri Lankan media on Saturday aired footage from security and street cameras in Colombo, Sri Lanka, showing how the suicide bombers entered the hotels before blowing themselves up.
A total of 253 people were killed in Sunday's series of six nearly-simultaneous bombings. A seventh attack occurred later the same day.
ISIS later claimed responsibility for the attacks.
The footage shows the suicide bombers examining the area, looking to the sides and choosing the exact spot from which each would carry out his attack.
Authorities initially estimated that the number of people killed was over 350, but later dropped the number due to many body parts being counted more than once.
"Some of the bodies get severely damaged in these kinds of explosions and it's possible for some bodies to get completely destroyed or break into parts, making the identification of full bodies difficult," CNN quoted a Health Ministry statement as saying. "Hence, counting an exact death toll is challenging."