MEXICO CITY (REUTERS) - Mexican police have detained a man who allegedly murdered four children and a woman in a small town in the centre of the country, authorites said on Saturday, as statistics show a marked increased in the number of women being murdered.

The state attorney's office in the town of San Luis Potosi said Filiberto Hernandez, 43, was detained on Thursday and confessed to five murders between 2010 and 2013. The office said he also raped his victims.

The crimes took place in Tamuin, a town of 16,000 southeast of San Luis Potosi, where Hernandez was a zumba and karate teacher.

The state attorney said it used the confession to find the remains of two of his victims, 9-year old Dulce Jimena Reyes, who disappeared in April, and Eliehoenai Chavez, 32, abducted in May after leaving the factory where she worked.

He is also alleged to have killed Adriana Martinez, found dead in 2011 at the age of 13 after disappearing on the way home from school.

State authorities are searching for the body of Rosa Maria Sanchez, missing since 2010 when she was 16, and that of 12-year old Itzel Castillo who disappeared in 2013, in fields close to where the others were found.

Since former President Felipe Calderon launched a military offensive on Mexico's drug cartels at the end of 2006, more than 85,000 people have died. Between 2007 and 2012, the total number of murders more than doubled, rising 112 percent.

Most victims were young men but the number of women killed shot up by more than one and a half times, 155 percent, to 2,764 in 2012, according to official data.