Police tape goes up every day in trouble spots all across Mexico but is rarely unfurled on the beach. One oceanfront stretch in Cancun, however, was closed off to the public recently after the federal government deemed it a crime scene -- the target of what prosecutors consider an elaborate scheme to steal sand. Federal police officers stormed the beach outside the Gran Caribe Real Cancun in late July and detained five hotel employees in the theft plot. Standing guard were heavily armed marines. After the arrests, the authorities closed off the beach with police tape as well as 'Closed' signs. Although Cancun has crystal-clear waters, plenty of sun and night life galore, its supply of sand has been dwindling for years, especially since Hurricane Wilma struck the Yucatan Peninsula hard and washed away much of the white granules four years ago. Now, narrow slivers of sand lie between Cancun's towering hotels and the waves. The government has spent tens of millions of dollars to replenish the beaches, but because those efforts have not kept up with Mother Nature, some hotel owners have taken measures into their own hands. At the Gran Caribe Real Cancun, workers built a breakwater into the ocean last year to reduce erosion and began pumping sand from the ocean floor to the shore. 'This was a protective measure to save the beach,' said Fernando Garcia Zalvidea, owner of the hotel, who was in Mexico City last week to meet with prosecutors. 'These tourists want sun and beach, and if they don't have it they get angry.' But the owners of some neighboring hotels got angry that Garcia's unauthorized public works projects were reducing the sand on their beaches. They complained to Mexico's attorney general for environmental protection, known as Profepa, which carried out the arrests and beach closing. Garcia suffered another blow on Monday when a Cancun court ruled against his challenge of the government's repeated orders to stop work. The dispute had been brewing for more than a year, with the hotel going to court while continuing its beach work. Garcia contended that his efforts were emergency projects that did not require government permission. In May 2008, seven other workers were arrested for carrying out the ocean construction at night. 'They were robbing sand, which is a property of the nation,' fumed Raziel Villegas Nunez, Profepa's director of oceanfront enforcement. As for the use of police tape, he said the unauthorized work, which included the introduction of a sand substitute known as sascab, was against the law and thus created a crime scene. 'We wanted to make it very clear it was closed,' he said. Some critics in Cancun have condemned the raid, saying the government had scared tourists at a time when visitors were already rattled by Mexico's drug violence and influenza outbreak. 'We're accused of being enemies of tourists,' responded Villegas. 'On the contrary. We're trying to take care of our natural resources, which is what the tourists come for.' Photographs from the scene showed troops standing by empty lounge chairs as well as bikini-clad hotel guests sneaking under the tape to get to the beach. As for any terror that the raid produced, Villegas produced a photograph of tourists posing with a camouflage-clad marine, his automatic weapon carefully pointed toward the sand. 