Accounts differ in regards to the kind of person that Bertha Jorkins was, but it's known to the reader from the beginning of the novel that Voldemort murdered her not long before the story starts and that she was an employee at the Ministry. Strangely, nobody tries to look for her until months after her disappearance. Sirius knew Bertha when they were at school and remembers her as not particularly smart but with an exceptionally good memory for gossip, while Dumbledore remembers that she had a habit of getting herself into trouble by chasing after juicy gossip. Ministry officials, however, talk about Bertha as being comically forgetful and often remark that they expect her to eventually show up in a country with a name that could somehow be confused with Albania, where she was purportedly headed when she disappeared. From Barty Crouch, Harry and Dumbledore learn that twelve years ago, Bertha discovered Barty in Mr. Crouch's home and when she confronted Mr. Crouch about it, his Memory Charm made her forget what she saw--but it also permanently damaged her memory and likely contributed to her reputation as forgetful. Wormtail ran into Bertha in Albania while on the hunt for Voldemort and, to maintain his own cover, took her with him to find his master. After breaking through Mr. Crouch's Memory Charm, Voldemort murdered her.