Owl Girl did not join The Owl in his crime-fighting escapades until issue #32 (Feb '42)of Crackajack Comics, 7 issues after her partner debutted in issue 25 (Feb '41). Not having superpowers both she and her senior partner relied on their fighting skills and various gimmicks, such as the Owl Mobile and a hand held "black light" that cast a beam of total darkness. Owl Girl (aka newspaper reporter Belle Wayne) was allowed to join police detective Nick Terry (aka The Owl) in his crimefighting endeavors after she discovered his secret identity. The duo also appeared in Dell's Popular Comics #72 - 85.
In this story she has tricked her way into an anti-USA sabotage ring in an effort to put an end to the ring's effectiveness. Her real identity is discovered, and she is apprehended at gun-point and chained in a holding cell, from which she is later rescued by her partner, the OWL himself. She eventually destroys the sabotuers as well as their hideout with a mighty explosion in which she uses their own weapons against them. As costumed heroines go, I think she looks quite good, but her crimefighting career was not long-lived. How unfortunate!!
Source: Comicsworld