MEXICO CITY - When Gustavo S�nchez became mayor in January of Tanc�taro, in the heart of Mexico's drug country, he knew the job made him a target of the violent drug cartels that have been targeting elected officials.

A tae kwon do instructor, he liked to joke that he had assembled a city council full of fighters.

"The fear is always there," he told The Arizona Republic in January. "But if you have courage and a desire to make a contribution, that outweighs the fear."

Last week, S�nchez's body was found by the side of a road, his head bashed in with rocks, his hands tied behind him. There were signs of torture.

He is the 11th mayor slain this year - the fifth since Aug. 16 - as the country's drug cartels tighten their control over rural Mexico. The violence is raising comparisons to war-torn Colombia, where dozens of mayors had to govern in exile during the 1990s after being run out of their towns by leftist guerillas who financed themselves with drug money.

"It's a show of force aimed at generating terror," said Ren� Jim�nez Ornelas, a crime expert at the National Autonomous University of Mexico.

"By eliminating mayors like they did in Colombia, they can move on to even higher levels of violence."

Some killings may be linked to disputes between mayors and drug lords, or punishment for a mayor suspected of helping federal police, said Dante Haro, a criminology professor at the University of Guadalajara. But other murders may just be aimed at intimidating citizens, he said.

"It's a demonstration," Haro said. "They're carrying out these (killings) to exert pressure."

Murders in Mexico have soared since December 2006, when President Felipe Calder�n ordered troops into smuggling hotspots to crack down on the cartels.

Since then, nearly 23,000 people have died in drug-related violence, according to an unofficial tally by the Reforma newspaper.

Until recently, most of the murdered officials have been from little-known villages.

But on Aug. 16, attackers kidnapped and killed the mayor of Santiago, a bedroom community just 15 miles from Monterrey, Mexico's wealthiest city. On Sept. 23, gunmen ambushed and killed the mayor of Doctor Gonz�lez, another Monterrey suburb, while he was driving to his ranch.

Tanc�taro, population 26,000, is in the central Mexican state of Michoac�n, where major marijuana fields and methamphetamine labs are located. In recent years, a drug gang known as the Familia Michoacana has been seizing control of the state's crime rackets, from prostitution to software piracy.

In December, gunmen kidnapped the fathers of Tanc�taro's town administrator and the city council secretary. Within hours, both officials resigned, along with the mayor, the entire city council, two administrators, the police chief and all 60 police officers. The fathers were then released.

The Michoac�n governor appointed S�nchez to run the town in January.

At the time, the 38-year-old mayor told The Republic he was concentrating on keeping the town services running and was steering clear of law-enforcement issues. With no town police left, fighting crime was the responsibility of federal police and troops, he said.

He was blunt when asked who ran the town.

"I can't tell you that it's me," he said. "Legally speaking, we're in charge. But no one is exempt from the pressure of those (criminal) groups."

In the weeks before he was killed, S�nchez showed no sign that he felt threatened, said town spokeswoman Marta L�pez Lozano. The mayor had led several group horseback rides to celebrate Mexico's bicentennial and inaugurated a number of street-paving projects.

"I was with him the whole time taking pictures, and everything was totally normal," L�pez said. "We didn't feel in danger."

On Sept. 26, S�nchez and the town's director for agricultural affairs, Rafael Equihua Cervantes, disappeared while driving back to Tanc�taro from the nearby town of Apatzingan.

Their bodies were found the next day, next to four large rocks that had been used to kill them.

"Nobody understands why he was killed," L�pez said.

No one has been convicted in any of the 11 murders of mayors this year, and federal police say the motives are unclear.

The killings are "something worrying and reprehensible," Calder�n's national security adviser, Alejandro Poir�, said after S�nchez's death. Mexico's Public Safety Secretariat was launching a study to identify at-risk mayors and offer them extra security, he said.

The deaths come as experts are voicing concern about the government's ability to maintain order.

In September, Secretary of State Hillary Clinton said the situation in Mexico was "looking more and more like Colombia looked 20 years ago," with drug traffickers controlling "certain parts of the country."

To combat lawlessness in small towns, the Calder�n administration on Wednesday filed a bill in Congress that would dissolve the country's municipal police and replace them with 32 state police forces.

"Many municipal police . . . are incapable of providing the confidence and the protection you need," Calder�n said in a letter to citizens announcing the bill.

In the long term, the violence against town officials may hurt Mexican democracy because many smart and qualified people are afraid to run for office, said Haro, the criminology professor.

"Before, it used to be an attractive job, living on the public payroll," he said. "Now being a town mayor is very difficult, not just because of the economic problems but also this issue of obedience to organized crime."

Getting elected now, he said, "is like winning a tiger in a raffle."

Sergio Solache contributed to this article.