Alice Guppy

Alice Guppy worked for Torchwood Cardiff (the future Torchwood 3) in the late Victorian era.

Profile
Arrested for theft, in 1898, future partner (possibly in more ways than one) Emily Holroyd contacted Guppy and offered her a pardon in exchange for working for the Torchwood Institute following the loss of another, male, operative who had also operated out of Cardiff. Holroyd believed that Guppy's willingness to steal and possibly kill could come in useful. (WEB: Torchwood.org.uk)

Emily and Alice, in turn, offered Jack Harkness a place working for Torchwood in Cardiff, after discovering that he couldn't die and that he possibly knew about the Doctor. Alice found Jack attractive but avowed that she found Emily more so than him. Alice came into conflict with Jack when he witnessed her cold-bloodedly executing a blowfish alien Jack captured on his first assignment. (TW: Fragments) Guppy, in fact, displayed sadism on several occasions, and took delight in torturing and physically assaulting Jack when first meeting him (TW: Fragments); there are signs she may have been mentally unbalanced (TW: Exit Wounds).

In 1901 by noticing energy signals, she discovered Jack, who had been buried by Gray and John Hart in 27 AD. (TW: Exit Wounds)

Alice apparently died while in service to Torchwood. As of the early 21st century, her body lay in cryogenic suspension in Bay 12 of the morgue of the Hub. (WEB: Torchwood.org.uk)

Behind the scenes
A Torchwood agent resembling Alice appears in the IDW Publishing Doctor Who comic, The Time Machination, however it is likely it isn't her as the story is set in 1889 and she joined Torchwood 9 years later.