M.O recovery

What exactly do you want to convey with "recovering the modus operandi" about the accused?

Can't you discuss the case history for better understanding of the experts, when nothing is clear from your query?

Unless the present status of the case is quite hazy to be understood by anyone, where arises the question of the precedent?

Well, if I'm assuming the meaning of your question correctly, I'd say yes, yes the presence of the accused would be necessary in court proceedings if his M.O. is necessarily established/to be established.