Lloyd Foster was William Harrison's Chief Financial Officer.
Trying to find some blackmail on Frank Buckley, they found out Harrison's "accident" death. Nick Monohan and Dylan Radcliff interviewed Lloyd Foster, his Chief Financial Officer and learned that possibly because of Buckley's having an affair with Vanessa hurting Devon (Harrison was very fond of her in a fatherly way), he threatened to shut down The Gates going so far as to have Foster going over the details of the possible shut down. Shortly afterward, Harrison was found dead due to falling down the stairs.
However the financial trail leads to a shell company called Rivertrace Land Management. Dylan tells Monohan that vampires have to reinvent themselves every 10 or so years because of their immortality set up shell companies to transfer their own money from their old identities to new ones, raising the possibility that Harrison was a vampire and he faked his death to move on. Later Dylan and Monohan would illegally disinter Harrison's supposed grave and did confirm it was him in it. Monohan also noted the crack in Harrison's skull inconsistent with a fall down stairs, showing that Harrison was indeed murdered.
The next day, having suspicions Monohan enlist Foster's help to help find Harrison's murderer who he states to Foster as being Buckley stating that he needs financial evidence as how Buckley supposedly was transferring funds to Rivertrace Land Management. However it was a trap - Monohan had tapped into the security camera at the shell company office and was watching remotely in his car. Foster was the one who entered the office with a box and brief case full of files, showing that he knew exactly what Rivertrace was. He proceeded to dump the box of files onto a desk, but then Buckley entered the office. Buckley quickly deduced that it was Foster that changed Harrison's will and then killed him. Foster shot Buckley just above the heart. He told Buckley that he came to tie up loose ends then squirted lighter fluid on Buckley and the dumped files in the office with the intent on burning both up. Foster then lights a lighter to ignite the place. However Monohan comes him and forces him at gunpoint to stop. Foster realizes it was a set up and Monohan told Foster that he revealed the position of the body of Harrison, "face down on the bottom of the stairs" in their first discussion. However, the crime scene photographs and and position of the body weren't made public. (Digging the Dirt)