Aristoteles Sandoval, the governor of the western Mexican state of Jalisco, speaks during a press conference. EFE/File

High-level commanders in the police force of the western Mexican state of Jalisco, where a wave of violence left seven people dead and 19 others wounded over the weekend, are working with drug traffickers, officers said Monday.

Officers who arrest a suspect must contact their superiors, who will order the individual released or held based on which gang he belongs to, a member of an elite state police unit told Radio Formula.

"If he belongs to the cartel that controls Jalisco at the time, they will order you to return the weapons and drugs, and for the arrest report or inspection to be tossed out. And the officers go (on their way)," the officer said.

Another police officer said commanders of the elite Fuerza Unica were working with the cartels.

"When you grab a cartel member and call the chiefs by phone, they tell you 'hang on,' and later they say, 'you know what, let him go, he's one of those people ... So, obviously, something fishy's going on," the officer said.

"The (Fuerza Unica) project is good ... but the commanders are worthless," the officer said.

The Cartel Jalisco Nueva Generacion set up 39 roadblocks last Friday in 25 Jalisco municipalities, leaving seven people dead and 19 others wounded.

Gov. Aristoteles Sandoval said the downing of a military helicopter and other attacks were staged in response to an operation aimed at arresting a cartel boss.

National Security Commissioner Monte Alejandro Rubido, meanwhile, said Monday that the death toll from the shootdown of the chopper had risen to six.

DNA tests confirmed that six soldiers died in the downing of the helicopter by the Cartel Jalisco Nueva Generacion, Rubido told Radio Formula, adding that the official figures initially listed three crewmen dead and three others missing.

The Cougar was attacked with a grenade launcher from a convoy on the Casimiro Castillo-Villa Purificacion highway, the national security commissioner said.

"We don't have hard evidence indicating" that Cartel Jalisco Nueva Generacion leader Nemesio Oseguera was in the convoy, "but we do know someone important in the criminal organization's hierarchy was there," Rubido said.

"They hit the tail rotor and the helicopter was able to maneuver and land," Rubido said, adding that 10 soldiers and police officers were injured in the incident.

"Operation Jalisco," which was launched on Friday and includes federal reinforcements, is designed to "strike a blow" at the cartel, "focusing on its operational, logistics and financial areas, and, of course, neutralizing all the targets," the national security commissioner said.

The Cartel Jalisco Nueva Generacion has "very significant firepower capabilities," Rubido said.

The criminal organization was created in Colima state and originally known as the Milenio cartel.

Oseguera took control of the cartel following the arrests of Oscar Nava Valencia in 2009 and Juan Carlos Nava Valencia in 2010.

The Cartel Jalisco Nueva Generacion "has expanded to other states, like Colima, Guanajuato, Michoacan, (and) they even have a presence in Veracruz," Rubido said.