Mexico nabs cop over 43 missing students

Mexican authorities have arrested a fugitive former deputy police chief wanted in connection with the disappearance of 43 students.

Francisco Salgado Valladares, who was deputy director of the southern city of Iguala's municipal force, was detained by federal police as he arrived for a meeting in Cuernavaca, some 90km south of Mexico City, the interior ministry said in a statement on Friday.

Prosecutors say Iguala's gang-linked mayor ordered police to intercept the students on September 26 over fears that the aspiring teachers, known for their regular protests, were in town to disrupt a speech by his wife.

Officers rounded up 43 students and handed them over to the Guerreros Unidos drug gang, which slaughtered the young men and incinerated their bodies, according to prosecutors.

The interior ministry said Salgado, 41, allegedly participated "in the detention and delivery of the students to members of organised crime".

Salgado ordered a fellow police commander in the neighbouring town of Cocula to take around 13 of the students "to be delivered to members of a criminal organisation", the statement said.

Salgado received around $US39,000 ($A49,000) per month to provide protection to the gang, the statement said.

Since the students disappeared, he had been hiding with relatives in the state of Guerrero, where Iguala is located, as well as Morelos, home to Cuernavaca, the ministry said.

Cartridges for an AK-47 rifle were found in his possession during is arrest.

Some 100 people have been detained in the case, including several Iguala and Cocula municipal officers, gang suspects, and Iguala's mayor Jose Luis Abarca and his wife.

The city's top security official, Felipe Flores Velazquez, remains on the lam in a case that has sparked protests against President Enrique Pena Nieto's administration.