FILE - In this Jan. 3, 2016, file photo, mourners carry the coffin of slain mayor of Temixco, Gisela Mota to the cemetery in Pueblo Viejo, Mexico. A survey published Aug. 11 by the newspaper Reforma put Mexico's President Enrique Pena Nieto’s approval rating at 23 percent, the lowest for any Mexican president since the paper began conducting the poll 21 years ago. Insecurity is a top concern for many Mexicans. Homicide rates dropped during the early part of his administration, which began in late 2012 and runs through 2018, but killings are up 16 percent over the first five months of this year from the same period in 2015. (AP Photo/Tony Rivera, File)

In this Sunday, Jan. 3, 2016 photo, mourners carry the coffin of slain mayor of Temixco, Gisela Mota, to the cemetery in Pueblo Viejo, Mexico. Mota took office as mayor of the city of on Jan. 1 and was shot at her home on Jan. 2. The governor of the southern Mexican state of Morelos says the killing of the mayor was a warning by drug gangs, meant to convince other officials to reject state police control of local forces. (AP Photo/Tony Rivera)

Mourners carry the coffin of slain mayor of Temixco, Gisela Mota, to the cemetery in Pueblo Viejo, Mexico, Sunday, Jan. 3, 2016. Mota took office as mayor of the city of on Jan. 1 and was shot at her home on Jan. 2. The governor of the southern Mexican state of Morelos says the killing of the mayor was a warning by drug gangs, meant to convince other officials to reject state police control of local forces. (AP Photo/Tony Rivera)

Mourners carry the coffin of slain mayor of Temixco, Gisela Mota, to the cemetery in Pueblo Viejo, Mexico, Sunday, Jan. 3, 2016. Mota took office as mayor of the city of on Jan. 1 and was shot at her home on Jan. 2. The governor of the southern Mexican state of Morelos says the killing of the mayor was a warning by drug gangs, meant to convince other officials to reject state police control of local forces. (AP Photo/Tony Rivera)

A man plays the accordion during the wake of the slain mayor of Temixco, Gisela Mota, at her home in Temixco, Mexico, Sunday, Jan. 3, 2016. Mota took office as mayor of the city of on Jan. 1 and was shot at her home on Jan. 2. The governor of the southern Mexican state of Morelos says the killing of the mayor was a warning by drug gangs, meant to convince other officials to reject state police control of local forces. (AP Photo/Tony Rivera)

Family members of the slain mayor of Temixco, Gisela Mota, mourn next to her casket, during a ceremony in her honor, at the mayor's office building of Temixco, Mexico, Sunday, Jan. 3, 2016. Mota took office as mayor of the city of on Jan. 1 and was shot at her home on Jan. 2. The governor of the southern Mexican state of Morelos says the killing of the mayor was a warning by drug gangs, meant to convince other officials to reject state police control of local forces. (AP Photo/Tony Rivera)

Mourners hug during a memorial mass for Gisela Mota, who was killed one day after taking office as mayor, at her home in Temixco, Morelos State, Mexico, Sunday, Jan. 3, 2106. Mota took office as mayor of the city of on Jan. 1 and was shot at her home on Jan. 2. The governor of the southern Mexican state of Morelos says the killing of the mayor was a warning by drug gangs, meant to convince other officials to reject state police control of local forces. (AP Photo/Tony Rivera)

Family members mourn during the wake of the slain mayor of Temixco, Gisela Mota, at her home in Temixco, Mexico, Sunday, Jan. 3, 2016. Mota took office as mayor of the city of on Jan. 1 and was shot at her home on Jan. 2. The governor of the southern Mexican state of Morelos says the killing of the mayor was a warning by drug gangs, meant to convince other officials to reject state police control of local forces. (AP Photo/Tony Rivera)

Forensic investigators inspect a car outside the home where Gisela Mota was killed, one day after taking office as mayor, in Temixco, Morelos State, Mexico, Saturday, Jan. 2, 2016. The Morelos state Public Security Commission says attackers invaded Mota's house on Saturday morning and killed her. Mota was sworn into office on New Year's Day. (AP Photo/Tony Rivera)

In this Friday, Jan. 1, 2016 photo, Gisela Mota waves during her swearing in ceremony as mayor of Temixco, Morelos State, Mexico. The Morelos state Public Security Commission says attackers invaded Mota's house on Saturday morning and killed her. (AP Photo/Tony Rivera)