[Cboldt]

It isn't clear to me what statute or statutes they were indicted on, although it can be inferred from the "as a member of a criminal street gang," that the prosecutor is charging under 71.02. Under that section, conspiracy is an offense, even if the accused doesn't directly assault a victim. A conspirator to assault (gang related or not) could be home in bed when the assault happened, and still be found guilty.

If there is no gang and/or no conspiracy, see Texas Penal Code Chapter 7, especially sections 7.01 through 7.03 for culpability being assigned to what is commonly referred to as "aider and abettor," or "accomplice." Those principle can attach to any crime, including the crime of assault.

[USNBandit]

I am not a lawyer, but if one was going to bring the assaults in as being part of a criminal gang I would think that statement would be part of the assault description. It is an interesting difference between the murder and assault statutes. I could easily see an assault law include being held accountable for the assaults committed by accomplices during another crime.