After an office-holder is impeaced the----- has the sole power to try the case.
Read this site carefully.
http://www.cnn.com/2008/POLITICS/12/16/blagojevich/
so it's the house of respresentatives right?
Right. :-)
The actual trial that leads to conviction et cetera takes place in the Senate.
After an office-holder is impeached, the Senate has the sole power to try the case.
To find this answer, you can consult the United States Constitution, specifically Article I, Section 3, Clause 6 which states, "The Senate shall have the sole Power to try all Impeachments." By researching or reading the Constitution, you can identify the branch of government responsible for trying impeachment cases.