New York, March 20 (RHC)-- Parents and colleagues of 43 students missing for nearly six months in Guerrero, Mexico, are taking their call for justice to the United States.

The students’ families question the Mexican government’s claims local police under orders from the corrupt mayor of Iguala turned the students over to drug gang members, who killed and incinerated them. Only one student’s remains have been identified, and Mexican media reports have tied federal authorities to the attack.

Three caravans will travel across the United States, converging on New York next month. Speaking at a news conference at the Mexican Consulate in New York, Felipe de la Cruz Sandoval, a professor at the Ayotzinapa teachers college -- whose son survived the police attack -- said the parents have a message for U.S. President Barack Obama.

Referring to arms deals between the U.S. and Mexico, the professor said that Obama should consider that a life is more important than an economic agreement on weapons with Mexico "because these weapons are being used to kill students in Mexico."