Name that technique:

My guess from his body and hands position is sankyo:

https://www.youtube.com/watch?v=2Ukep2YSsxI

Looks like ikkyo or oshi taoshi.

I agree ikkyo

It's Ikkyo in shape, but it's certainly not Aikido.

It's oshi taoshi with a reverse grip. Very close to one of the Shodokan goshin-ho (application) variations.

It was interesting to watch and I would not call it a body slam - most action just involved the arm of the lady and that was enough. I have no idea what went on before but the cop just put her down with very little force - pretty aikido-esque to me.

Indeed that reverse grip has me confused. I've seen similar Sankyo variations with the same grip and body positioning. But again the mechanics can also be Ikkyo or Oshi Taoshi. Anyway it certainly wasn't a body slam.

What they said.
Gyaku ikkyo

...I think they're just saying her body slammed into the ground; it could be described as aikido or [insert art that does that movement here]. I'd be curious to know what the training system of the officer was...I like aikido-esque.

I'd say it's sankyō (kote hineri) with the suspect being a non-compliant (and non-pliable) aite, rather than a trained uke that knows how to preserve herself.

Anyway, if you carefully watch the footage, you can see the police officer slip in, at the same time "corkscrewing" her hand, followed by taking her tegatana with his right hand. (That initial part looks a bit like what my sensei does when he is trying to jump to highlighting the details of the takedown, rather than to demonstrate the full attack response). The officer's left hand is completely free during the takedown. The corkscrew, the tegatana grip, and the free hand would seem to indicate sankyō (kote hineri) rather than ikkyō (oshi taoshi).

During the takedown, he kind of jerks his body rather than properly using his hips, which would indicate to me that he probably learned the technique in a self-defense crash-course for police officers and security guards (so he probably didn't have much time in class to learn about "preserving uke"). Even with the officer's body movement being jerky & ugly, I'd still say he was doing the small circle variant of the sankyō takedown, which seems to be the less common in Aikido (by my limited experience). At the same time, I have had some partners that seem to prefer the small circle version, so it can't be too uncommon. The small circle version feels like it leaves a smaller margin of error for uke (my experience as uke).

At any rate, the course instructor could well have been an Aikido or a Hapkido practitioner. Hapkido also uses what we would call sankyō, and they largely use small circle variants, so perhaps it's that, but I've willing to chalk up most of the variation just being due to the suspected crash-course learning I mentioned early.

It is "straight arm takedown", a very common DT/Arresting technique for LEO's all around the world.

That clip made me angry.

Demetrio Cereijo wrote: It is "straight arm takedown", a very common DT/Arresting technique for LEO's all around the world.

Similar but again different execution. Also it's no surprise that those techniques are similar to Aikido techniques, they are restraining techniques after all that are used around the world by police and military personnel.

What is the correct Japanese name of this technique?

https://www.youtube.com/watch?v=HnLE8nDqpA0

Igor Vojnović wrote: What is the correct Japanese name of this technique? https://www.youtube.com/watch?v=HnLE8nDqpA0

Maki Otoshi variation, perhaps?

In Shizuo Imaizumi's Shin-Budo Kai organization, they have a rather nice convention to naming techniques - <attack><throw><modifier>. In that convention, this technique would probably be called something like:

Shomen-uchi Zenpo-nage Sudori (Front head strike, forward direction throw, passing through)

To specify the absolute requirement of dropping to one knee, one might use the additional modifier Orishiki.