<P> Damon reveals that he's spent his entire existence of being a vampire loving Katherine and focusing on freeing her from the tomb she's been trapped in for the last 145 years . After opening the tomb, Damon realizes that Katherine had been free this whole time; although she knew where he was at times, she never cared to see him . Damon is heartbroken . </P> <P> Katherine had help to escape, but all the other vampires had desiccated in the tomb . When the tomb spell failed to be put back up, they were able to feed on blood Damon had brought for Katherine and escaped . Feeling vengeful toward Mystic Falls and the town's founding families, the tomb vampires plotted an attack for Founder's Day . Katherine needed the tomb vampires dead so Klaus wouldn't find out she was still alive . She enlisted the help of her descendant and friend, Isobel, to retrieve one of Johnathan Gilbert's inventions, a weapon against vampires . The device was given to John Gilbert to round up and kill the tomb vampires during their planned attack on the town . </P> <P> After the chaos has settled, Katherine, having stolen some of Elena Gilbert's clothes, goes to the Gilbert house and poses as Elena in the presence of Damon . After a heartfelt confession from Damon, he kisses her, not yet realizing Katherine has returned to Mystic Falls . The two are interrupted by Elena's aunt, Jenna Sommers, who is still unaware of the presence of vampires or the existence of Katherine . Jenna tells Elena to come in, which gives Katherine the invitation she needs to get into the house . Katherine startles John Gilbert in the kitchen, still pretending to be Elena . She notices the magic ring he is wearing and uses a butcher's knife to viciously chop off his fingers, then stabs him . Elena arrives and comes to John's aid while Katherine hovers behind him . </P> <P> Seeing John seriously injured, Elena calls for help and is terrified by Katherine's super-speed around the house before leaving . At the mayor's wake at the Lockwood mansion, Katherine engages in a small power play with Bonnie, claiming that it never ends well for Bennett witches . Bonnie attempts her usual attack against vampires, but Katherine, a much older vampire than Bonnie is used to encountering, seems to have a certain amount of resistance to such spells . </P>

When do they kill katherine in vampire diaries