GEOFF BENNETT: A Russian-American dual citizen who's been living and working in Los Angeles has been detained in Russia, accused of treason and of fund-raising for Ukraine; 33-year-old Ksenia Karelina was in Russia visiting her family when she was arrested.

And now her boyfriend is pleading for help.

And Chris van Heerden joins us now.

Thank you for being with us.

And, Chris, first tell us about Ksenia.

What do you want the world to know about her?

CHRIS VAN HEERDEN, Boyfriend of Ksenia Karelina: That she's a normal person, that she's kind, loving, funny, loved by all her friends.

Everyone who meets wants more of Ksenia.

She is - - she's -- she's the light that walks into the room.

Everyone wants her attention.

She's happy.

She has so much life in her.

That's Ksenia.

GEOFF BENNETT: Why did she decide to travel to Russia?

And was she at all concerned that something this might happen, given Moscow's practice of detaining foreign citizens and Russian dual citizens?

CHRIS VAN HEERDEN: The reason -- the reason was, she wanted to go see her family, especially the grandparents.

She hasn't been home since pre-COVID.

And she really -- she was -- she told me.

She said: "I'm afraid I might lose my grandparents.

They're very old, and I want to go see them."

She was not concerned at all, not at all, not even a little bit.

I was.

And I made it clear to her.

I said: "I don't think it's a good idea to go."

But she convinced me that no.

I mean, she's Russian, and there's no bombs dropping in Russia.

"Like, I'm safe."

And she told me that Yekaterinburg is so far in the middle of nowhere that she has nothing to worry about.

And she honestly had -- she didn't look she like had fear.

And -- but then again, she doesn't watch the news.

I know she doesn't follow the news.

So I don't think she knew what she was doing.

GEOFF BENNETT: At first, as I understand it, her detention was brief.

Russian authorities took her cell phone, and then they released her.

And then what happened?

CHRIS VAN HEERDEN: Then she went home.

And she was home for three weeks.

And two days before the 27th, January 27, when I really spoke to her again like every other day, I said: "What's happening?

Like, you're flying in two days to come back to me?"

And she said: "Oh, baby.

It's all over.

Like, they phoned me and said I can come and pick up my phone in an hour.

I just need to go and sign some stuff."

And she honestly was -- she seemed so relieved that she can finally just breathe.

And that was the last I spoke to her.

I haven't heard from her then.

GEOFF BENNETT: She now faces up to 20 years in a Russian prison for the alleged crime of donating $50 to a charity that supports Ukraine.

When you think about that potential sentence, what goes through your mind?

CHRIS VAN HEERDEN: I am trying not to think about it.

But knowing Ksenia, knowing how much life she has, she has -- and knowing how she lives her day-to-day, I can honestly not imagine.

I cannot believe it.

GEOFF BENNETT: I'm sure you have seen this video released by the FSB purportedly showing Ksenia being led blindfolded and having cuffs put on her.

What do you know about her well-being right now?

CHRIS VAN HEERDEN: She wrote me a letter two days ago.

She wrote me a letter.

I received a letter from her two days ago.

She's safe.

She's locked up with two women, and kind people, she says.

But that's what she say about everyone.

She was a little sick, apparently.

And she had a bad cough, but that cough is going away.

One moment, she's in good spirits and she believes she will come out and see me soon, and, one moment, she tells herself that she might be in there for life.

I just know she's safe.

She told me: "I'm safe."

GEOFF BENNETT: Have you or her family heard anything from U.S. officials?

CHRIS VAN HEERDEN: I spoke to the U.S. State Department.

No one can tell me anything, because it's confidential.

And they need to get letters to Ksenia to sign in order for them to speak to me.

And they said they will do that.

And I asked, when?

And they had no answer for me.

That's all -- that's all they said to me.

GEOFF BENNETT: Well, Chris van Heerden, we certainly wish the best for Ksenia and for you and her family.

Thank you for being with us.

CHRIS VAN HEERDEN: Thank you so much.