A spokeswoman at the Boston police department directed all questions on the suspects to the FBI, which has yet to disclose their identities, the department said in a brief item posted Wednesday on its Twitter account.
The message said more details would follow.
Dzhokhar Tsarnaev, a 19-year-old college student, is charged with killing three and injuring more than 200 in the two bombs last month.
His brother, Tamerlan Tsarnaev, 26, was killed in a confrontation with police in Watertown several days afterward as the two tried to flee the area. Police say they were trying to subdue him when his brother ran him over in a desperate escape.
More details to fololow