Authorities say the suitcase bore a hand-lettered sign referring to the Familia Michoacana drug cartel. Police say the sign read: "Don't steal from the Familia Michoacana. You're next, Jonas."
A police official who was not authorized to speak on the record said Monday that the woman's head and hands had been cut off.
The cartel was once based in the violence-wracked western state of Michoacan, but has reportedly expanded to Mexico City suburbs.
The capital has largely been spared the cartel violence that afflicts many regions, but some happens. Last May, 12 young people were kidnapped from a Mexico City club and killed, apparently by a drug gang.
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