MEXICO CITY — Mexican authorities said Wednesday that investigators found no immediate signs of foul play in the plane crash that killed the country's interior minister and 13 other people.
The crash, which killed Interior Minister Juan Camilo Mourino and eight others aboard a Learjet 45 on Tuesday night, was a serious blow to President Felipe Calderon at a time when his government is locked in a violent struggle against drug traffickers and faces growing signs of economic trouble related to the global downturn.
As interior minister, traditionally the country's second- most powerful office, the 37-year-old Mourino's sprawling portfolio included domestic security. He was the closest among Calderon's tight circle of advisors on crime and a host of other issues and had been mentioned as a possible successor when Calderon's term ends in 2012.
"It's a strong blow," said Alfonso Zarate, a political analyst in Mexico City. "It is the loss of a key figure from some of the most sensitive issues in the country."
But Mourino did not carry the political heft of some of his predecessors, and commentators already had started asking how long he would last in the post. He was interior minister for just 10 months and took a back seat to the army and other federal law enforcement officials in the crime fight, analysts said.
Mourino's death seems unlikely to significantly alter the course of Calderon's 2-year-old, uphill campaign against drug traffickers.
"He may have been incredibly important, personally, to the president. But it's hard to see where the ship of state has been affected," said Daniel Lund, a Mexico City-based pollster and political consultant.
Also killed was a former top anti-drug prosecutor, Jose Luis Santiago Vasconcelos, spurring immediate suspicion that the plane crash might have been the work of criminal gangs. Mexico's public safety director, Ramon Martin Huerta, died three years ago in a helicopter crash that was deemed an accident.
Luis Tellez, the transportation secretary, said Tuesday's crash did not appear to involve an explosion before the plane hit the ground, reducing the likelihood that a bomb had been planted.
"We have detected no evidence leading to a hypothesis other than an accident," Tellez told reporters. "But it will be investigated until all possibilities are exhausted."
He said the inquiry could take weeks. Officials said U.S. and British air crash investigators would join the investigation. Specialists from the U.S. National Transportation Safety Board arrived early Wednesday.
In an effort to stanch rumors, Mexican officials took the unusual step of releasing radar images and radio exchanges between the pilot and air traffic controllers. The pilot did not report any problems before controllers lost contact.
Tellez said the investigators would analyze flight data from the plane's "black box."
At least five people were killed on the ground. The plane went down in dense rush-hour traffic next to a busy boulevard, the Paseo de la Reforma. Witnesses described a fiery explosion. At least 40 people were injured, many of them hospitalized with severe burns.
Guillermo Ortiz, a 30-year-old waiter, said the plane looked as though it was preparing to land, then veered toward office buildings nearby.
"Then it hit the ground -- boom! -- and it all started: the flames, noise," he said. "There was a taxi stand and the guy that sells tortas -- I'm sure they're all dead."
Mexican authorities covered the site with blue, orange and green tarps as investigators looked for evidence. Soldiers stood by while curious passersby snapped cellphone pictures and shared conspiracy theories. Crumpled, burned cars were still visible. A glassy high-rise was charred black.
"We will never know what really happened," said Jose Perez Flores, 73, a retired government worker. "There is something fishy going on. Between the politicians, the narcos -- who knows. That's what we've come to here in Mexico."
Mexican politicians issued messages of sympathy for the loss of Mourino, and the main newspapers carried full-page condolence notices.
In Washington, Homeland Security Secretary Michael Chertoff praised Mourino as a "courageous and strong partner" in the binational fight against organized crime.
Calderon did not signal who would take over as interior minister, a post that oversees a wide array of functions, including security and disaster relief, and serves as the link between the president and Congress. Mourino's deputy, Abraham Gonzalez Uyeda, will serve as interim minister.
Calderon was thought to be grooming Mourino, his former chief of staff, as the next standard-bearer of their conservative National Action Party.
But Mourino was hobbled early on by criticism from leftist political foes, who accused him of having acted on behalf of his family's gasoline business when he served as a top energy official. He also was a leading target for critics who said the administration was losing its battle against organized crime.
Mexico has been awash in violence since Calderon launched his war on drug traffickers in December 2006. This year, about 4,000 people have been died in drug violence, much of it bloody turf wars between competing smuggling organizations.
Times staff writer Tracy Wilkinson contributed to this report.