Federal Attorney General Rafael Macedo de la Concha also said at least four other officers, including a state commander, were on the run. The commander, Miguel Angel Loya, has not shown up for work since Monday, said state police spokesman Mauro Conde.
The officers were arrested in northern Mexico and brought to Mexico City.
The 11 victims apparently were bound, gagged and suffocated or shot by suspected drug traffickers, then buried in shallow graves at a house in Ciudad Juarez connected to the Vicente Carrillo drug gang.
Macedo de la Concha has said the victims apparently were rivals of the cartel and had been dead for as long as a year. The bodies were found over the weekend.
The house was rented by Alejandro Garcia, who allegedly told police he helped kill and bury victims in his backyard at the behest of a top Vicente Carrillo drug gang leader and several Mexican state police officers — and he believes there are still more dead to be found.
Mexican investigators said the property apparently was used by Humberto Santillan, who was arrested Jan. 15 across the border in El Paso, Texas. Mexican authorities identified Santillan as a chief lieutenant for the gang.
Garcia said he worked with the Carrillo cartel for a year.
The 13 arrested officers worked the night shift, starting at 8 p.m. and getting off at 8 a.m., Conde said. The money from drug trafficking is "too tempting for people who are not committed to public service," he said.
The arrests expose a police force long believed to be inept and corrupt. For a decade, hundreds of slayings have gone unsolved, particularly those involving a string of young women killed in a similar manner.
Some people said they were not surprised by the arrests.
"We all knew they were behind this," said Luz Elena Caraveo, whose brother disappeared along with his friend a year ago — allegedly after being kidnapped by police.
"One is always afraid to talk and look (for answers) because one could easily become a target."
State officials have tried to purge the police ranks of corruption, firing some 300 officers in the last two years, Conde said.
"Since they started these investigations, we have cooperated with the attorney general," he said. "We have always tried to clean up these bad elements."
Lorenza Benavides, vice president of the Association of Relatives and Friends of the Disappeared, said her organization has received reports of 197 missing men and the number keeps growing.
"We have always said police officers are involved in all of these crimes," Benavides said. "But our complaints have always fallen on deaf ears."
Benavides said her organization has asked federal authorities to search three homes around Ciudad Juarez where neighbors reported hearing screams and seeing many people come in and out.
Deputy Attorney General Jose Luis Santiago Vasconcelos said those homes will be searched soon. A total of six homes in Ciudad Juarez are involved in the investigation, he said.