Prosecutors allege a Mexico City man kept his two teenage stepdaughters captive for five years, fathered five children with them, then killed one of them and one of his children.
Authorities say Jorge Iniestra beat one of the teens to death in 2009 and asphyxiated a 3-month-old boy he fathered with her sister by forcing the baby to nurse from the dead girl's body.
Prosecutor Jorge Ferman says Iniestra kept the bodies in his mother's home in a poor borough for a month. He says Iniestra and a brother then dumped the bodies on a road leading to neighboring Mexico State.
Ferman says the teenagers' mother was Iniestra's girlfriend and she recently denounced him to police.
Both Iniestra and the girlfriend have been detained.