Two U.S. officials say the surviving suspected Boston bomber told interrogators that he and his brother considered setting off their bombs on July Fourth, but they decided to carry out their attack sooner and chose the date of the Boston marathon.

The U.S. officials say Dzhokhar Tsarnaev told investigators the bombs were assembled in his brother’s home.

The officials spoke on condition of anonymity because they were not authorized to publicly discuss the details because the investigation into the Boston marathon attack is ongoing.

Dzhokhar Tsarnaev (joh-HAHR’ tsahr-NEYE’-ehv) faces a charge of using a weapon of mass destruction to kill. His brother, Tamerlan, was killed in a police shootout.

Three people died and more than 260 were injured in the Boston marathon attack.