The death toll was one of the heaviest to hit Mexico since President Enrique Pena Nieto took office in December 2012.
Mexico Institute for Social Security has stopped vaccines nationwide as a precaution.
State prosecutors spokesman Randy Suastegui says gunmen fired on state police who were responding to a reported kidnapping.
Mexican authorities say the number of dead from a recent gasoline truck blast has reached 20 after 2 more people succumbed to injuries.
Gomez was arrested at a house in Morelia, the capital of Michoacan, along with eight bodyguards.
An investigation was underway to determine whether the bus driver was trying to beat the train.
10 people fleeting from their kidnappers were found in Guerrero were located by Mexican soldiers on Sunday.
Televisa station suffers a grenade attack in Mexico border city, leaves 2 injured.
To protest the recent increase in killings and disappearances of journalists, Hay Festival will take place online instead of Xalapa city.
The explosion occurred when a tanker truck was making a routine delivery of gas to the hospital kitchen.
The place where the body was found was not far from where Khalsa was last seen in a picture of himself.
Rajdeep Sardesai questioned where the journalism, that took public interest into account, was.
Mexico City is bracing for demonstrations as caravans of students and family members of missing students converge.
Authorities in the northern Mexican state of Tamaulipas say six people have been killed in a small plane crash.
Police in the Mexican border state of Tamaulipas wounded a pregnant 14-year-old US citizen.