Dala

Dala was an alien con artist of an unknown species, who impersonated the Starfleet Captain Kathryn Janeway in 2376.

Using this deception, she and her partners Mobar and Zar were able to move from star system to star system offering services for different goods from the various races, but not delivering what they promised. Since USS Voyager and Janeway were being blamed, Janeway believed that in order to make things right she and the crew of Voyager had to stop Dala.

Dala and one of her partners were posing as monks, when they met Neelix and Tom Paris while they were on an away mission. They downloaded the database from the Delta Flyer, which provided them with information about Voyager and its crew so they could pose as Janeway and Tuvok. They then stole ten kilotons of bolomite from the Telsian miners and committed other scams. After Dala was captured by Voyager, she refused to tell the location of the stolen property. Janeway allowed Dala to escape, and she led them to her partners. The Doctor assumed her identity and tricked them into revealing the location of the stolen property. Dala was handed over to the authorities. 

Dala