Did they told you where Alice was killed? Guard a the entrance, that sounds reasonable. But Manager assistant? How good do you know her. Do you think she could have been involved? That she may know attackers? Does she know your AccessID?
Since they have been beaten to death, I dont think atackers needed any special amunintion...well if they used explosives to destroy Lucom nexus, that would be your cup of tea.
Mouse, exactly my idea, and when we are in UCAS, this may work. Id be very interested to have a look at those security feeds they collected...and step by step story of What-really-happens-there should be helpfull also.