My roommate and a former friend of his were talking on twitter, roommate gives out his address and tells the assailant to “roll up at any time.” Assailant shows up at our door, the roommate responds, and then, without notice, the assailant throws a punch at my roommate and throws him into my bathroom. The altercation gradually de-escalates and leaves the attacker. My toilet had been broken in the brawl, my roommate had obvious signs of physical damage, and neither he nor myself had been hit by the attacker, just grappled with him until he calmed down.
Since my friend called the assailant out, would this be a joint attack, or should we openly press charges since the assailant charged our home without invitation and started attacking my roommate?