According to CBS News, the three people arrested are friends of Dzhokhar Tsarnaev.
Two will be charged with conspiracy to obstruct justice and making false statements. They are not U.S. citizens.
According to WBZ-TVs Karen Anderson, their names are Azamat Tazhayakov and Dias Kadyrbayev. Both are originally from Kazakhstan and attended the University of Massachusetts at Dartmouth with Dzhokhar Tsarnaev.
The third suspect, according to CBS News, is an American citizen and he will be charged with making false statements.
Sources told CBS News senior correspondent John Miller that investigators arrested the three for harboring or aiding the Tsarnaev brothers after the fact. These will be federal charges.