Law enforcement folks: What does "DSO" stand for?

[Paladin]

They're playing a lot of recordings of the Capitol Police during the 1/6/2021 riot at the hearings today, and officers in really extreme situations are shouting "DSO" a lot. I couldn't find anything online. Thanks for your help.

[intrepidity]

1. my WAG

distress several officers?

[robbob]

8. WAG??

“Wild Ass Guess”? 😁

[better]

2. Looks like maybe "District Staff Officer" (nt)

[scarletwoman]

3. Domestic Security Operation?

[DeminPennswoods]

10. This what Maddow said

although she wasn't 100% certain. She said it was a call for the LE units that are trained for riot control and have the proper equipment like tear gas, pepper spray, etc.

[magicarpet]

4. This help,.... ?

D.I.E: Died In Emergency

DOA: Dead On Arrival

DOB: Date of Birth

DOS: Dead on Scene

DOT: Direction of Travel

DUI: Driving under the Influence

DWI: Driving While Intoxicated

[maspirit]

5. Division of Special Operations

https://mpdc.dc.gov/page/special-operations-division

[mahatmakanejeeves]

7. Thanks. Welcome to DU. NT (no text in the "Message text" box)

[AmyStrange]

9. Welcome to the DU!

[Paladin]

6. Thanks for all the responses. (nt)