He was taken hostage, along with his staff, by Mordan's ruler, Karnas. Karnas used the hostages to lure AdmiralMark Jameson to Mordan in order to gain revenge on him.
According to Karnas, Hawkins and the other abductees would be killed by their "terrorist captors" if Jameson did not arrive on Mordan IV in six Earthdays.
Prior to Hawkins' residing on Mordan IV, Jameson had briefed him on the planet's status. When William T. Riker raised the question of how Karnas knew that Jameson still lived, the ambassador mentioned his briefing of Hawkins and suggested that the ambassador may have told him so. (TNG: "Too Short a Season")