KUALA LUMPUR, Malaysia — The two women who claim they were tricked into assassinating the estranged half brother of North Korea’s leader appeared in court Thursday, where their lawyers argued that Malaysia’s decision to free three North Korean suspects ended any chance of bringing the real culprits to justice.

The prime minister of Malaysia, Najib Razak, allowed the three suspects to leave the country two weeks ago in a deal his government negotiated with North Korea, making the women, one from Indonesia and one from Vietnam, the only suspects likely to be charged in the killing.

“That’s tantamount to a miscarriage of justice,” said Gooi Soon Seng, the lawyer representing the accused Indonesian, Siti Aisyah, in an interview after the court hearing. “The two girls are mere scapegoats. They are naïve girls who have been used by these people.”

Ms. Siti, 25, and Doan Thi Huong, 28, are accused of smearing VX nerve agent, a banned chemical weapon, on the face of Kim Jong-nam, the half brother of Kim Jong-un, at the Kuala Lumpur airport in February.