American prisons were no match for Maru, who quickly escaped and fled to China.  In December of 1943, she was operating as undercover agent Mei Sing, a dancing girl and a gentleman’s club near a Chinese air base.  Steve Trevor, on a mission in China, recognized “Mei Sing” but cannot place her until she lures him to her dressing room and sedates him with special tea.  From there, she and her girls head for air force base and steal a plan to fly to a Japanese base nearby.  As she takes off, a gas bomb left by her girls explodes, flooding the engines of nearby planes and paralyzing them.

Regaining consciousness in Japanese custody, Trevor uses his access to Wonder Woman’s mental radio to alert him to his predictament, sending her flying in an Amazon plane to his rescue.  She arrives and recognizes Poison as her old adversary but is overcome by Maru’s gas weapons.  Before succumbing, she summons her remodeled Invisible Jet, that she can now control by telepathy.   Maru leaves after taunting her captives that she will use her gas to disable the entire US military, allowing the base to be destroyed to cover their tracks.   In the carnage, Wonder Woman escapes with the unconscious Trevor and battles her way through Japanese forces until her plane arrives to help her escape.  Snatching Maru up with her lasso, she takes off for an American airfield.  Under the influence of her lasso, Maru reveals that her plans had not been delivered to the Japanese as of yet and thus with her in custody, America’s planes were Safe (Sensation Comics #24).

The activities of Maru, either as Doctor Poison or otherwise, are unknown for several years.  Whether she was taken back into military custody or delivered to the reform colony controlled by the Amazons is not clear.  What is known is that by 1948, she was a prisoner on Transformation Island when the Saturnian military operative Evilless staged a mass escape, freeing her and several other adversaries of Wonder Woman.  United, these women formed the criminal group Villainy Inc.   They quickly capture Hippolyta and in short order, all of the Amazons. Hippolyta manages to alert Wonder Woman who rushes to her aid.  Initially captured and held captive with Hippolyta, the escape of several for Amazon prisoners disrupts the operations and several of Villainy Inc., including Dr. Poison, are soon captured and presumable returned to the programs of reform (Wonder Woman #28).

The later activities of Doctor Poison are unrevealed.