Mexico City (CNN) -- As Mexican President Felipe Calderon mourned the loss of his top minister in the nation's war against drug cartels, he pledged that the investigation into Friday's helicopter crash that killed the Cabinet member and all seven others aboard would be transparent and timely.
In a national address Friday, Calderon said authorities don't know the exact cause of the crash south of Mexico City that killed Interior Minister Jose Francisco Blake Mora, but he added that investigators will look at all possible angles.
A total of eight people -- not nine as earlier indicated by a government spokeswoman -- were killed in the crash, which occurred in a rural area south of the nation's capital.
The incident evoked comparisons to a 2008 plane crash that also killed the country's then-interior minister. That crash, in a luxurious Mexico City neighborhood, was later determined to be an accident caused by turbulence. The Learjet carrying the minister and others was following a commercial airliner too closely, authorities said.
On Friday, Calderon called Blake Mora "a great Mexican who deeply loved his country and served until the last moment of his life."
Analysts said that the crash puts renewed attention on the president's controversial efforts to fight the nation's notorious cartels because the interior minister oversees domestic security.
"The national mood is such that even before this, people are alarmed" about cartel violence, said Stephen Zamora, a professor at the University of Houston Law Center who's an expert on Mexican law and U.S.-Mexico relations.
"Calderon is in the last year of his presidency, so Mexico is entering a presidential election year just as the United States is. President Calderon has been criticized because the number of persons killed has escalated during his presidency and so people see him as failed. I think that's a harsh judgment," Zamora said.
"He inherited a country, especially in the northern states, that is being destabilized by the drug cartels. He's started employing the army, which hasn't been used much domestically, to fight the drug cartels," Zamora said.
While Blake Mora was well regarded by U.S. officials, his loss won't devastate the Calderon administration, said Pamela K. Starr, associate professor of international relations at the University of Southern California.
"I think there's an inevitability that there will be speculation that organized crime was involved in this, but it seems highly unlikely to me that indeed will be the case," Starr said, noting how the helicopter crashed under foggy conditions in a remote area.
"He was very highly thought of both within Mexico and with his counterparts in the United States," Starr said of Blake Mora. "With that said, he has not been one of the central figures in the battle against drug cartels in Mexico. The lead has been taken more by the federal police and the president himself, along with the military and the prosecutor's office."
The helicopter went down in the Xochimilco area south of Mexico City on Friday, government spokeswoman Alejandra Sota said.
Also killed in the crash were Undersecretary for Legal Affairs and Human Rights Felipe Zamora and the ministry's press office chief, Jose Alfredo Garcia, she said.
In July 2010, Calderon appointed Blake Mora to the post that oversees security efforts against drug cartels in Mexico. That battle has cost thousands of lives.
"I grieve his loss" and those of the other victims, Calderon said in a national address, adding that Blake Mora, who was 45, leaves behind a wife and two children.
Authorities are investigating the cause of the accident. A photograph of the crash site depicts a relatively concentrated debris field. The French-manufactured Super Puma THP06 helicopter was made in 1987 and had logged 717 hours of flight, Mexican officials said.
Before becoming interior minister, Blake Mora was an attorney from Baja California state who was chief of staff to the state government from 2007 until July 2010. Previously, he was a councilman in Tijuana, as well as a state and federal congressman.
Blake Mora was considered to be politically close to the president and, in fact, led his political campaign in Baja California.
The helicopter crashed while traveling between Mexico City and the Mexican state of Morelos south of the city, officials said.
At a news conference, Sota confirmed there were no survivors and said the president met with Blake Mora's widow.
The others killed were Diana Miriam Hayton Sanchez, a technical secretary; Lt. Maj. Rene de Leon Sapien; and three members of the air force: Lt. Felipe Basio Cortes, Lt. Pedro Ramon Becerra Escobar and Sgt. Jorge Luis Juarez Gomez.
Ironically, Blake Mora's last writing in his Twitter account refers to the November 2008 accident that killed the prior interior minister.
"Today we remember Juan Camilo Mourino three years after his departure, a human being who worked on building a better Mexico," Blake Mora wrote in a tweet posted November 4, the third anniversary of the accident.
Mourino died when his plane, returning to Mexico City after a tour of work in the state of San Luis Potosi, crashed near the intersection of Mexico City's Periferico beltway and its grand boulevard, the Paseo de la Reforma.
No foul play was suspected in that accident, officials said.
An investigation led by Gilberto Lopez Meyer, head of the nation's Airports and Auxiliary Services agency, determined that the Learjet 45 carrying the minister was too close to a Boeing 767 and the pilots lost control in the larger jet's wake.
The Learjet slammed into the capital's wealthy Lomas neighborhood, killing all eight people on board and six on the ground. At least 40 others on the ground were injured.
Former Interior Secretary Santiago Creel reacted to Friday's crash on Twitter by saying: "I'm sorry the accident. My prayers for Francis Blake and the other crew are found safe and sound."
When appointed interior minister in 2010, Blake Mora succeeded Fernando Gomez Mont, who resigned as Calderon reorganized his Cabinet. A senior presidential adviser, Patricia Flores Elizondo, also resigned.
CNN's Michael Martinez, who wrote from Los Angeles, Mariano Castillo and CNNMexico.com contributed to this report.