Andy Dell was one of the major leaders of the Earth Defenders Group, a league of eco-terrorists. Informant Haley Kerns and Detective Benson went undercover to sabotage an attempted bombing on a GMO food company with a history also of animal testing.
Dell worked as a security guard in the company under an assumed name to get within its systems, being the access to the local chapter breaking in the night of the attack. Haley, brainwashed by the group, double-crossed Benson and started setting up a bomb, revealing the truth about the operation. After Agent Dana Lewis shot Haley dead, the rest of the group was arrested, and Dell escaped.
When the FBI found out he was headed to Oregon, Benson was recruited to infiltrate deeper to track him and his accomplices by posing as arrested member Persephone James. Benson then went off the grid with Agent Dean Porter as her handler. (SVU: "Informed")
When Dell and other leaders were jailed and otherwise taken down and the EDG founder was found to have already been in custody in Montreal, Beson was relieved from undercover assignment and reinstated in Manhattan SVU. (SVU: "Infiltrated")