Server Crash

Someone is able to crash our server currently; before every crash I see this…

Crazy origin, angles, velocity, angular velocity on entity [755][prop_physics]
Origin: [-1.#IND00, -1.#IND00, 1.#QNAN0]
Angles: [-1.#IND00, 1.#QNAN0, 180.000000]
Velocity: [-1.#IND00, -1.#IND00, 1.#QNAN0]
Angular Velocity: [-1.#IND00, -1.#IND00, 1.#QNAN0]

Also saw someone welding props and pulling them apart; but this happens before EVERY crash, any ideas?

Is your server running on Windows? If so, is your server creating any mdmp files next to srcds.exe?

Yes; it is running windows.

No; I do not see any mdmp files.

Is it an instant crash? Does it lag before? Do you have a console log of your server before it crashed? If you need help, try to give as much info as possible!