Mexican government is accused of a cover up over deadly three-hour gun fight which killed 42 cartel and one police officer

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The Mexican government is being accused of a cover up after 42 suspected cartel members and one police officer died in a fierce three-hour gunfight which erupted on a ranch in western Mexico.

Eyewitnesses describe a scene of utter carnage, with dead bodies of men without shirts and some without shoes strewn over the ranch.

But as investigators and human rights officials continued to work at the scene on Saturday, questions were being raised about the government's version of events. 

Security expert Alejandro Hope called the government's version of what happened at the ranch 'weird.' 

Killing field: Federal police stand near the bodies of men who authorities say were suspected cartel gunmen at the Rancho del Sol, near Ecuanduero, in western Mexico, Friday, May 22, 2015

Gun battle: At least 43 people died Friday in what authorities described as a fierce, three-hour gun battle between federal forces and suspected drug gang gunmen at the ranch

Carnage: Vehicles are left in a corner as they burn followng the gun battle, in a warehouse at Rancho del Sol,

He noted there were more dead than weapons recovered and he said in some of the photos it appeared the corpses had been moved.

Hope, formerly worked for Mexico's national intelligence agency. 

He said: 'There are many, many still obscure pieces of information.'

According to police, the call for backup at the ranch went out to local police after 8 a.m. when federal authorities said they needed help.

One patrolman said he sped with his colleagues from a town 20 minutes away and arrived at the scene Friday to see bullets flying and military and police helicopters hovering overhead.

The scene was one of the deadliest confrontations with suspected cartel members in recent memory. 

Investigation: Police comb a field for evidence in the Rancho del Sol, a ranch in the municipality of Ecuandureo, Mexico

The deadly shootout took place in an area near the Michoacan border with Jalisco state.

It is known to be a stronghold of the Jalisco New Generation cartel, one of the most powerful and fastest-growing organized crime groups to surface in recent years.   

The bodies, some appearing to lie with semi-automatic rifles, lay in fields, next to farm equipment and on a blood-stained patio strewn with clothes, mattresses and sleeping bags.

'It looked like a battlefield,' an officer said Saturday. 

Guillermo Trejo, political science professor who studies Mexico at the University of Notre Dame said: 'Is this a massacre or battle, illegal executions or routine operations?' regarding the ranch battle.

'We need to ask these questions because there is a short and long history of the government fabricating and staging the scenes of battles and crimes.  

This comes as questions still linger over the disappearance of 43 college students last September And the killing of more than nine people in January in Michoacan.

Witnesses in Michacan said they came out of their cars shouting they were unarmed. The government said they were suspected criminals who were killed by friendly fire. 

Evidence: The clash was the deadliest confrontation in recent memory, with 42 suspected gang gunmen and one Federal Police officer killed on Friday during a three-hour firefight at this remote western ranch

Back up: Police arrive at the Rancho del Sol, a ranch that was the site of clashes between Mexican authorities and a drug cartel, in the municipality of Ecuandureo, Mexico, Saturday, May 23, 2015

Location: Police drive along a road inside the Rancho del Sol, after the horrific battle which left 43 dead

Mexican officials are now scrambling to work out what started the bloody battle at the ranch. 

Mexico's national intelligence agency said the Mexican government is suffering a 'serious credibility deficit.

Patrol cars were parked at the 112-hectare (277-acre) property known as Rancho de Sol as police guarded all entrances to the property.

National Security Commissioner Monte Alejandro Rubido wouldn't name the cartel, but said the responsible group has its base in Jalisco state.

Government officials said the shooting broke out early Friday as federal authorities responded to a complaint of armed men taking over the ranch.

Federal forces heading to the ranch met a truck carrying armed men who opened fire, and when government forces chased the gunmen onto the ranch, they came under heavy fire from others, Rubido said.

Authorities detained three people and confiscated 36 semi-automatic weapons, two smaller arms, a grenade launcher that had been fired and a .50-caliber rifle, Rubido said.

He said eight vehicles also were confiscated, six of them set ablaze by a fire inside a storehouse that created a black plume of smoke seen for miles.

Yet, despite the accounts of shooting, the lack of federal casualties raised questions because of a similar case last June 30 in Mexico state, where the army said 22 alleged criminals died in a shootout with troops, while only one soldier was injured. 

An investigation by The Associated Press also revealed that many of the suspects had been killed after they surrendered.