General:
* Involved
* Connected
* Associated
* Linked
* Entangled
* Mixed up
* Drawn into
* Compromised
More specific:
* Accused (if it suggests wrongdoing)
* Suspected (if it suggests uncertainty)
* Charged (if it's a formal accusation)
* Blamed (if it suggests responsibility)
* Incriminated (if it suggests strong evidence)
The best synonym will depend on the specific situation and the nuances of the meaning.