You are looking at the unfortunate Lavinia. She is a non-character in the movies, but does play some role in the novels.
Note - If you go to any of these links, there are spoilers for the third book. If you haven't read it, be wary. From the Wikipedia she is:
An Avox (a servant whose tongue has been cut out as punishment for
treason). She has red hair, pale skin, and striking features. Because
of her inability to speak, Katniss initially does not know her name or
anything about her. Katniss recognizes her from when she and Gale
witnessed the girl's capture and the death of her friend, and Katniss
later speculates that she is a runaway from the Capitol.
To explain what an Avox is, from the Hunger Games Wiki:
An Avox is a person who has been punished for being a rebel against
the Capitol; a traitor or a runaway. Avoxes have had their tongues cut
out, rendering them mute. They are used as domestic servants and
waiter upon tributes and Capitol citizens. It is also suggested that
Avoxes are charged with the day-to-day maintenance of the Capitol and
work shifts in the Transfer network under the city. The term "avox" is
from Latin, meaning "without a voice."
Some more information about Lavinia, again from the Hunger Games Wiki:
Before she became an Avox, Lavinia and an unknown boy, whom Katniss
believed was her brother or lover, were seen by Katniss and Gale while
they were out hunting, in an off-limits wood outside of District 12.
They appeared to be escaping from the Capitol for unknown reasons, and
Katniss noted that the two had a "Capitol look" to them. A Capitol
hovercraft appeared; the boy was struck with a spear that was shot
from the hovercraft and was killed instantly, then was lifted up to
the hovercraft, not to be mentioned again in the series. Lavinia,
however, was scooped up by a net and taken into the hovercraft, and
she briefly locked eyes with Katniss and Gale. When the boy was
killed, she screamed what sounded like a name, and Katniss wondered if
it was the name of the boy.
Years later, Lavinia waited on Katniss as an Avox whose tongue had
been cut out for committing crimes against the Capitol. Katniss said
she knew Lavinia, but at that time did not know her name or where she
remembered her from. This worried the residents from the Capitol, so
Peeta stepped in and claimed that Lavinia looked like Delly Cartwright
- a girl from District 12 who went to school with them, and who Katniss claims, could be the nicest person on earth. As an Avox, she
could not publicly acknowledge anything that was not a direct order,
so Katniss' initial attempt at conversation was ignored. However when
she later walks in on the mess Katniss has made in her room prior to
interview night she shows some response to Katniss' attempted apology,
indicating by gestures that Katniss did not need to be sorry, and that
there was nothing she could have done, otherwise she too, would have
been an Avox.
Finally, some trivia from the same page:
She is the only known Capitol citizen who attempted to escape for
She is not mentioned in The Hunger Games film due to
the thought that her presence would have been rendered useless and
would not have mattered anyway.
Lavinia is also the name of a
character in Shakespeare's play Titus Andronicus. In the play, Lavinia
has her tongue removed after she is assaulted so she will not reveal
who attacked her.
She's a truly tragic character and certainly a memorable one from the books.