Sunday’s midday shooting death of Vice Adm. Carlos Miguel Salazar Ramonet and one of his assistants has sent shock waves through Mexico. The death of such a high-level military officer is a rarity in Mexico’s drug war, and the navy is considered the nation’s most elite and trustworthy fighting force.

The attack was one of numerous violent assaults on federal authorities in the state of Michoacan in recent weeks. Seven federal police officers have been killed, and many more wounded. More than 20 alleged criminals have also died in the shootouts.

Many here assume that the attacks were coordinated and carried out by the Caballeros Templarios, or Knights Templar, a cartel that runs an extensive and violent extortion racket in Michoacan. The Knights may be lashing out in response to the increased number of federal forces that began arriving in May to try to regain territory that the cartel essentially controls.

It appears that Salazar was not in Michoacan on assignment. At a news conference, Mexican Atty. Gen. Jesus Murillo Karam said that Salazar had been visiting family members in an undisclosed part of Mexico and was being driven back to Puerto Vallarta, in the neighboring state of Jalisco, where he had been based. He was traveling in a white Chevrolet Suburban with his wife, his assistant and a driver.

When Salazar discovered that the freeway he was traveling on was blocked, he decided to take a secondary road, where another truck blocked his path, Murillo Karam said. The people in the truck began asking the Suburban’s occupants for identification, when a second truck pulled up. The people inside the second truck opened fire on the Suburban.

The vice admiral covered his wife, getting her to the floor of the vehicle. But he was killed, along with the assistant, while trying to fight back, Murillo Karam said.

The wife and the driver were injured, but were “out of danger” as of Monday afternoon, according to Eduardo Sanchez, a government spokesman.

The three men arrested for taking part in the attack confessed their involvement, Murillo Karam said, “or at least [to being] the occupants of one of the trucks.” The men, according to the prosecutor, also acknowledged working as robbers, kidnappers and extortionists for the Knights Templar, earning monthly salaries of 7,500 pesos, or about $590.

That detail that goes a long way toward explaining the allure of the cartels in a country where minimum wage workers  earn roughly 1,430 pesos per month, or $112.

Murillo Karam said it was “important to note that the admiral wasn’t wearing a uniform, that he was going like any other citizen, much like many citizens who have visited their family on the weekend and were coming back to go to work.”  But the attackers might have deduced that Salazar was a top government official, particularly given his use of the Suburban, a favorite car among Mexico’s elite.

Whether Salazar was singled out or picked at random, the episode highlights the challenge President Enrique Peña Nieto faces as he tries to bring peace to Michoacan, a state he has acknowledged is partly controlled by cartels.

On Monday, Peña Nieto said the attack and incidents like it reaffirm the need to impose the rule of law throughout the country.

Avila, 52, was arrested in 2007 in Mexico City with her Colombian boyfriend, Juan Diego Espinoza Ramirez, who pleaded guilty to cocaine trafficking charges two years later. A Mexican judge acquitted Avila of drug-related charges in 2010, but she was extradited to the United States to face charges that she conspired to import more than 11 pounds of cocaine into the U.S.

Officials alleged Avila was an important link between Colombian cocaine suppliers and Mexican drug groups. It is rare for a woman to face such charges, and this fact, in addition to her glamour, vanity and smiling insouciance — she once had a doctor visit her in prison to give her Botox treatments — turned her into a kind of drug war folk figure. She was interviewed by CNN’s Anderson Cooper, and the Mexican musical group Los Tucanes de Tijuana wrote a well-known narcocorrido about her.

Avila has always claimed she was an innocent homemaker. In a plea agreement with prosecutors in April, the drug charges were dropped, and Avila admitted to an accessory charge for helping to hide her boyfriend from authorities, according to Avila’s U.S. attorney, Stephen J. Ralls.

Ralls, in a phone interview Thursday, said that U.S. District Judge K. Michael Moore, in sentencing Avila, also gave her credit for time served while in custody in Mexico and the U.S. She was still behind bars Thursday evening, but Ralls said it is probably just a matter of days before she is freed.

Ralls said that U.S. officials would probably send her back to Mexico soon, where she is not facing any further charges. Alberto Islas, a spokesman for the Mexican attorney general, said that his office “has no order of apprehension against Sandra Avila, nor is there any inquest open against her.”

Authorities first became suspicious of Avila in 2001 after her son was kidnapped and she was reportedly able to pay a multimillion-dollar ransom to get him back.

Cecilia Sanchez of The Times’ Mexico City bureau contributed to this report.

Doctors at Mexico City’s Central Military Hospital plan to remove a thyroid nodule during the July 31 operation, after which Peña Nieto will have a four-day recovery period at Los Pinos, the MexicanWhite House.

The thyroid gland is in the neck, below the voice box. Among other things, it helps regulate metabolism.

According to the American Thyroid Assn. website, thyroid nodule removal surgery may be necessary for a number of reasons. A biopsy may have determined that the nodule is cancerous, or possibly cancerous. Surgery may also be necessary if a biopsy was inconclusive. Nodules known to be non-cancerous may need to be removed if they are large, or causing pain.

The statement from the president’s office did not say which of these might be the case for Peña Nieto, and a spokesman declined to comment.

Peña Nieto, of Mexico’s Institutional Revolutionary Party, or PRI, was elected in July 2012 and took office in December. He is pressing for a series of proposed institutional reforms that he says are designed to make Mexican government more modern and efficient.

this month, he finished a Mexico City 10K road race (6.2 miles) in a respectable 54 minutes, 8 seconds.

The brazen attacks, which also left 15 police officers injured, underscored the challenge the Mexican government faces in a southwestern state that, while long plagued by outlaw groups, has suffered from intense new waves of cartel violence. The conflict is detracting from President Enrique Peña Nieto’s effort to steer the world’s attention away from Mexico’s drug war and toward the country’s economic potential.

The instability in Michoacan ratcheted up in recent months as armed “self-defense” groups rose up to fight off the state’s dominant cartel, the Knights Templar, who, in addition to their drug operations, have engaged in a widespread campaign of extortion, rape and killings of everyday citizens.

The incidents, which include a deadly ambush on federal police and the slaying of two people in a medical clinic by gunmen disguised as doctors,  demonstrate how much work President Enrique Peña Nieto has yet to do to convince his countrymen that Mexico is becoming safer.

In June, six months after Peña Nieto’s swearing-in, his government boasted that in both February and May the number of homicides connected to federal crimes fell below 1,000 per month. (Drug and organized crime cases are usually under federal jurisdiction in Mexico.)

Statistics for June showed that the symbolically important 1,000 figure again had not been breached, with 869 homicides reported by the Interior Ministry. Before February, it had been surpassed every month for three straight years.

But the seemingly unrelated acts of violence in recent days is a rebuke to anyone who thinks the country’s problems are solved.

The ambush of the federal officers occurred Thursday in the southwestern state of Michoacan, on a highway near the border with the state of Guerrero. Three officers were slain and six were wounded, according to the state prosecutor’s office.

A day later, the bodies of two men and two women were found hanging at the entrance to the Michoacan community of El Limon de la Luna, in a municipality called Buenavista Tomatlan. The farming region, in the western portion of Michoacan known as the Tierra Caliente (Hot Land), has beenone of the most unstable in Mexico in recent months, with vigilante groups taking up arms to defend themselves from a narcotics cartel called the Knights Templar. Peña Nieto sent the military to the region in May in an effort to restore order.

There is a concern that some of the vigilante groups have been infiltrated by members of a rival drug cartel. On Monday, according to media and government reports, a group of protesters in the western Michoacan city of Los Reyes marched on city hall, reportedly accompanied by members of a self-defense group who planned to kick out the municipal police, whom they suspected of supporting the Knights Templar.

The news agency Notimex reported that the protesters were fired on by members of a second group whose identity is unknown. Mexican papers Monday reported that as many as five people were killed in the attack. The state’s governor confirmed Monday via Twitter that one woman had been killed.

In the neighboring state of Jalisco, officials said seven people were slain in a 12-hour period Saturday in greater Guadalajara, Mexico’s second-largest metropolitan area and the longtime home of a number of narco bosses. Among the victims, officials said, were a state police officer and a municipal police officer from Puerto Vallarta.

In the state of Durango, to Jalisco’s north, eight people were slain Friday in three municipalities. The next day, three burned bodies were discovered in a home in the city of Lerdo.

In the border state of Coahuila, 18 people were slain in various incidents in the capital, Saltillo, between Friday and Sunday. Gunmen who dressed as doctors carried out an attack in a medical clinic in Torreon, state officials said.

Last week, the leader of the notorious Zetas drug cartel, Angel Treviño Morales, was captured by federal officials, and many had speculated that a wave of bloodshed would follow. But it is not clear if any of the recent events are connected to his detention.

In addition to army and navy troops who have been fighting the drug cartels since 2006, the federal government next year plans to introduce 4,000 to 5,000 members of a new gendarmerie, a special police force with military training that Peña Nieto promised during his campaign.

“We are defining their functions, where they are going to be and what they are going to do,” said Manuel Mondragon y Kalb, the national security commissioner, in a television interview this month.

Copyright © 2013, Los Angeles Times

Photo: Mexican President Enrique Peña Nieto (Mexican President’s Office, via LA Times)

It was unclear whether Alberto Lopez Bello was attacked in retaliation for his work for El Imparcial, a newspaper in the city of Oaxaca, the state capital. The paper published a brief statement Wednesday demanding a thorough investigation and saying the killing “demonstrates the vulnerability to which communicators are exposed in their daily work of providing truthful and timely information to the citizenry.” [link in Spanish]

The Oaxacan state government said that Lopez’s body was found along with the corpse of another man in Trinidad de Viguera, a city north of the Oaxacan capital. The news website Milenio reportedthat Lopez suffered gunshot wounds. [link in Spanish]

The second man was identified by state officials as Arturo Alejandro Franco Rojas. Milenio reported that Franco worked for a municipal police intelligence unit.

Mexico remains one of the most dangerous places in the world for journalists.

Lopez was the fourth journalist slain during the seven months that President Enrique Peña Nieto has been in office. According to the Committee to Protect Journalists, 53 journalists were killed or vanished during the six-year term of former President Felipe Calderon, Peña Nieto’s predecessor.

Oaxacan Gov.  Gabino Cue instructed the state prosecutor’s office to refer the case to the federal attorney general. In May, Mexico passed a law giving federal prosecutors more authority to take up cases involving crimes against journalists.

Sanchez is a researcher in The Times’ Mexico City bureau.