The long arm of the law has gone bionic.

Mexico's attorney general, Rafael Macedo de la Concha, announced this week that he has a microchip implanted in one of his arms. The chip, enclosed in a sleek capsule about the size of a grain of rice, emits a low-frequency radio wave that can be used to locate Macedo, as he told reporters, "at any moment, wherever I am."

The chips also function as an electronic identification that grants Macedo and about 160 of his lieutenants access to a suite of offices on the third floor of the attorney general's headquarters, which houses a state-of-the-art, $30 million computerized database of crime, which President Vicente Fox inaugurated Monday.

A scanner at the door reads the identification numbers in the chips. Once scanned and recognized, Macedo and the others are permitted to enter the offices, where officials are focused on using computers to organize and analyze crime statistics. Analysts said Mexico's lack of centralized and computerized crime data is a key reason that most crimes here are never solved.

Fox has faced growing public dissatisfaction with high crime rates. Hundreds of thousands of Mexicans crammed Mexico City's main square last month, carrying signs that said "Enough Already" and demanding more government action against kidnappers, robbers and other criminals.

The chips, injected through a syringe-like device, are the latest and most high-tech weapons in the government's offensive against crime, prompting jokes in Wednesday's newspapers that Macedo was Mexico's "Robocop."

"Macedo has every right to put in a chip and look like Robocop, but he should think first about people who don't have so much protection," said Jose Antonio Ortega, a lawyer and president of the security commission of Coparmex, a prominent business association. Ortega said he doesn't know any Mexican business owners who have had chips implanted. He said that given all Macedo's bodyguards and armored vehicles, having a chip was "a joke."

About 1,000 people in Mexico have had the VeriChip implanted, said Antonio Aceves, president of Solusat, the Mexican distributor of the chip, which was created by a Florida company, Applied Digital Solutions. He said most of the customers have been people with medical problems, including diabetes and Alzheimer's disease. The chip can be programmed to carry medical information, which can be read by scanners that several Mexico City hospitals now have, he said.

Aceves said only a few people had bought the chip for security purposes, including one family that had one implanted in their 2-year-old daughter. He said the company hopes that the chips can ultimately make door keys obsolete; he said home doors could be equipped to read the chips of residents.

Armando Martinez, a shopkeeper in Mexico City's Coyoacan neighborhood, had another idea.

"All politicians should get one," he said, "because then we would know where they are when they steal our money."

A microchip like the one the Mexican attorney general had placed in his arm serves as a locater and an ID.