AMNA NAWAZ: Princeton graduate student Elizabeth Tsurkov has been missing for six months.

A dual Russian-Israeli citizen with family in the u.s., she was conducting research for her doctoral degree in Baghdad, when she was believed to be kidnapped by an Iraqi militia.

I spoke recently with her sister, Emma Tsurkov, who lives in the U.S. and has been trying to get government officials and Princeton to do more to bring her sister home.

I asked Emma how she first learned that her sister had been taken.

EMMA TSURKOV, Sister of Elizabeth Tsurkov: We're very close.

We text each other daily.

And she loves my son, her only nephew, so much.

He's the apple of her eye, truly.

And no matter what's going on, and even if she is mad at me, she will always respond to pictures of him.

So I sent her a picture of him, and then a few hours went by.

And then, at the point at which it was 12 hours, and she has not responded, I knew something must be wrong.

There is no way that she's OK and has not responded to a picture of him.

And then I started making phone calls and trying to understand what's going on.

I contacted the Russian authorities.

I contacted the Israeli authorities to try and understand what's happening.

And from that point on, that's basically the way this started.

AMNA NAWAZ: So she's believed to be held by a group of people called Kataib Hezbollah.

It's an Iranian-backed Shia militia in Iraq.

Since she was taken, have you heard anything from her or from them?

Do you understand why she would have been kidnapped?

EMMA TSURKOV: So, I have not heard from them.

I have not received any demands.

I -- they have kidnapped her because she is Jewish.

She is a Jewish woman at the hands of an extremist terrorist organization.

So, she is a completely innocent woman, a brilliant scholar, and a very kind person.

She has done nothing wrong to anyone and does not deserve to languish at the hands of a terror organization.

AMNA NAWAZ: You have been in touch with a number of officials in Russia, in Israel, also in Iraq, also here in the U.S. You even stood outside the Iraqi embassy, I understand with a sign, trying to get a meeting with the ambassador.

But amid all of these countries, who do you think is responsible?

Who should take the lead in trying to get your sister out?

EMMA TSURKOV: So, I believe that the United States is uniquely positioned to help secure my sister's release, for several reasons, first of all, because my sister has a strong relationship to the U.S.

While she is not a citizen, she is a resident of the state of New Jersey.

She is a graduate student at Princeton University.

And, more importantly, I will point to the fact that the U.S. government provides aid to the Iraqi government that funds the organization that kidnapped her.

The U.S. government needs to apply pressure to the Iraqi government to do everything they can to free my sister, because, currently, that's not happening.

AMNA NAWAZ: She was there doing work as part of her degree at Princeton.

It was reviewed by Princeton in advance, approved by Princeton in advance.

What have your conversations been like with them so far?

EMMA TSURKOV: Unfortunately, they have been very frustrating.

I expected Princeton to be a strong ally of mine and help get my sister back.

But, in fact, what they have done is treat it mainly as a P.R.

problem.

I was passed from one administrative person to another.

Princeton had started this whisper campaign in which the Israeli and the U.S. governments were told that -- which is untrue -- that she was there on her own.

And all of that is deeply damaging to my sister's case and to her chances of survival.

This isn't a matter of P.R.

or of liability.

It is literally life or death for her.

AMNA NAWAZ: You have been meeting with U.S. officials here on your visit to Washington.

Have any of them said that they will help to take the lead to secure her release?

EMMA TSURKOV: So, I have letters from members of Congress, Representative Eric Swalwell, who represents the district I live in California, and Senators Menendez and Booker, in which they ask the State Department to do more to get the Iraqi government to intervene and do more to free my sister.

But it seems that, so far, everyone is passing the buck.

Everyone wants to know what's happening, but no one wants to take the lead and take the responsibility of doing everything possible to bring my sister back.

She's an amazing, kind, brilliant person, and she doesn't deserve this.

She doesn't deserve this.

AMNA NAWAZ: That is Emma Tsurkov, sister of Elizabeth Tsurkov.

Emma, thank you so much for being here.

We appreciate it.

EMMA TSURKOV: Thank you for having me.

AMNA NAWAZ: In a statement to the "NewsHour," Princeton University called Elizabeth Tsurkov a valued member of their community, saying there's been ongoing contact with government officials and experts to understand how Princeton can best support her safe return.