TIJUANA – The 57 laborers detained at the massive marijuana field discovered south of Ensenada said they were being forced to work there against their will, said Baja California's human rights ombudsman.

But federal authorities said the men are members of an organized crime group. They are being held at El Hongo, the state penitentiary near Tecate, awaiting prosecution.

For his part, Baja California Attorney General Rommel Moreno said the case is a federal matter. In an interview, he said he didn't know if the laborers had been forced to work at the 300-acre field near El Rosario, the largest marijuana farm ever found in Mexico.

The state's human rights ombudsman said the workers' claims need to be investigated.

"There needs to be an investigation as to what happened in the field because they could have been forced to work there," said Heriberto García. "I don't know if the authorities bothered to investigate if the men were hired or taken there against their will."

His staff interviewed the 57 laborers who were detained near the field, all from Sinaloa. The staff members wanted to know the workers' legal situation, their health and if their family knew they had been arrested.

Only 21 provided a phone number of a family member in Sinaloa, but only seven of those numbers worked to contact a relative. In the remaining cases, the staff only left phone messages.

The laborers said that they were not told what they would be doing when they were hired, García said. Some had worked the field between 30 and 45 days. All had been paid about one thousand pesos ($83). They said that they lived and slept near the field and were not allowed to leave.

Since the criminal case against the laborers is a federal matter, their claims will be taken up by the National Human Rights Commission. García said that his office is working with his counterpart in Sinaloa to try to find the workers' families.

A total of 58 laborers were arrested when the Mexican army raided the field but one of them was released because he was a minor. Authorities estimate that the marijuana would have had a street value of $150 million had it reached market.

During a press conference Saturday, Gilberto Landeros, the commander of the Second Military Zone, explained that surveillance flights had not detected the immense marijuana field earlier because the plants appeared to be tomatoes. Plus the field was covered by a black net. It took a foot patrol by soldiers to make a positive identification.

On Aug. 1 a district judge ordered the 57 men to be detained, among them Alejandro Navarrete Aldana, who allegedly owns the property.

Authorities believe that the "mega field" belonged to the Sinaloa cartel, a powerful criminal organization led by Joaquín "El Chapo" Guzmán and Ismael "El Mayo" Zambada.

omar.millan@sandiegored.com