There would be several reasons it would be legal and appropriate to stand an employee down. Most obvious is safety in regard to the employee being able to do their job adequately while under the high pressure of standing accused, whether guilty or not. Then you have other issues such as what if the accused decides to do something stupid to evade capture at some point, etc...
Now stand down without pay is another issue, I assume that is more what you would debate.
Once you are charged with a serious offence and remanded in custody I assume pay would be suspended until resolved.