Eli Loker is the lead researcher at the Lightman Group. This character conducts voice stress tests in order to see where various spikes take place, as these can indicate deception.
Eli possesses an interesting quality, as well: he refuses to lie. Loker has taken a pledge to be radically honest. Makes for a helpful dynamic at a company that makes a living trying to get at the truth.
Lightman: No Loker, I just leave it lying around so plonkers like you think I am clever.
Eli: It could be Emily's.