|Portrayed by||Alice Rietveld|
|Name||Isla or Ilsa|
|First appearance||Strawberries and Cream|
|Last appearance||Strawberries and Cream|
Isla or Ilsa was a presumed professional assassin and accomplice sent by Red John when the serial killer learned of Madeleine Hightower's whereabouts. She was sent in to kill her, but ignoring completely that Lisbon's Team was using her as a bait to figure out who was the CBI mole by previously telling 5 different people Craig O'Laughlin, Oscar Ardiles, J.J. LaRoche, Brenda Shettrick and Gale Bertram a different room number where Madeleine was although Madeleine was not in any of the rooms. She went to Gale Bertram's room number leading Lisbon's team to the impression that Bertram was the mole, although in reality she was going to use the rope to climb down to Craig O'Laughlin's room as he was the real mole. However, before she could rope down, Rigsby and Cho came into the room forcing her to jump off the railing and kill herself (probably Red John hypnotised her to tell her to do it, if she's discovered) due to how far she fell.