(CNN) -- Investigators have found residue of explosives in the Cambridge, Massachusetts, apartment slain bombing suspect Tamerlan Tsarnaev shared with his wife and young daughter, a source briefed on the investigation told CNN on Friday.

The residue turned up in at least three places, the source said: the kitchen table, the kitchen sink and the bathtub.

Suspect Dzhokhar Tsarnaev had previously told investigators that he and his brother built the devices in Tamerlan's home, according to another U.S. law enforcement official regularly briefed on the investigation.

http://www.cnn.com/2013/05/03/us/boston-attack/index.html?hpt=hp_t1