According to Hamilton, who is also Talia Winters's uncle, the bombing on Babylon 5 was really an attempt by Arthur Malten to rid himself of political opponents within Psi Corps.
In the canteen, there were gasps of surprise and an occasional I told you so! Everyone put down their Ping-Pong paddles and pool cues to listen to the gruesome details, which included two fatal bombings, dozens of deaths, and the murder of Emily Crane? Then his skin began to blister and fall away in tatters.