Last week, Julio Cesar Godoy was a congressman-elect. This week, he is a fugitive.

Mexican authorities say Godoy, a half-brother of Michoacan state Gov. Leonel Godoy, helped provide protection for La Familia, the drug-trafficking gang that has waged war on federal police across the state in recent days, killing at least 16 officers.

Officials have an arrest warrant but apparently can’t find the younger Godoy, an attorney who was elected to Congress on July 5 as a candidate of the left-leaning Democratic Revolution Party, or PRD.

Feeling political heat, Gov. Godoy on Wednesday called on his sibling to turn himself in and confront the accusations. Godoy said his half-brother lived in a modest house, drove a used Volkswagen and showed no signs of links to organized crime. The two last spoke weeks ago, the governor said.

“He has to present his evidence if he is innocent,” Godoy said in a radio interview. “If he is guilty, let them punish him with the full weight of the law.”

The younger Godoy has not been seen in public since the campaign closed July 1. He didn’t show up to vote on election day nor, after his victory, to collect the official notification that he had been elected to Congress.

Authorities, who did not specify when the arrest order was granted, announced the allegations Tuesday as part of the investigation into a string of attacks in Michoacan against federal police officers since Saturday. The attacks, including the slayings of 12 federal officers whose bodies were dumped near a highway, appeared to be in retaliation for the arrest of Arnoldo Rueda Medina, described as one of the gang’s top three figures.

Officials say Saul Solis, a failed Green Party candidate for Congress, is also being sought for his alleged role as liaison between the crime group and officials and businessmen in Michoacan.

The allegations add new force to concerns over how thoroughly drug traffickers have infiltrated Mexico’s political system, especially in smuggling crossroads such as Michoacan.

“Cartels like La Familia are born, grow and reproduce thanks to narco-politics, thanks to the complicity of those in power and the cloak of impunity that protects them,” columnist Ricardo Aleman wrote Wednesday in El Universal newspaper.

The charges against Julio Cesar Godoy brought fresh pressure on his half-brother. Gov. Godoy, a member of the same political party, already faced questions after the state’s attorney general and other aides were among 30 local and state functionaries arrested in May over suspected ties to La Familia.

The governor has dismissed the arrests as an election-season stunt by the administration of Mexican President Felipe Calderon, of the conservative National Action Party. And he rejected fresh calls to resign.

“I won’t give them the pleasure,” Godoy said Wednesday.

Monte Alejandro Rubido, a national security spokesman, said that a senior gunman arrested in the recent attacks revealed details about La Familia’s structure. He said Julio Cesar Godoy and Solis worked for the group’s alleged operations chief, Servando Gomez Martinez, who lives in Michoacan.

A man who said he was Gomez Martinez phoned a public affairs television show in Michoacan on Wednesday and called on Calderon to reach an accord with La Familia.

Hours later, Interior Minister Fernando Gomez Mont rejected the purported overture, saying Mexico would not negotiate with any criminal group.

ken.ellingwood@latimes.com