U.S. authorities confirmed Monday that Jenni Rivera, a U.S.-born singer whose soulful voice and openness about her personal troubles made her a Mexican-American superstar, was killed in a plane crash in northern Mexico.

The National Transportation Safety Board said it was sending a team to help investigate the crash, and the board said Mexican authorities had informed them that Rivera had died in the accident.

Rivera's relatives in the U.S. already had few doubts that she was on the Learjet 25 that disintegrated on impact Sunday in rugged territory in Nuevo Leon state in northern Mexico.

"My son Lupillo told me that effectively it was Jenni's plane that crashed and that everyone on board died," her father, Pedro Rivera, told dozens of reporters gathered in front of his Los Angeles-area home. "I believe my daughter's body is unrecognizable."

He said that his son would fly to Monterrey Monday.

Messages of condolence

Messages of condolence poured in from fellow musicians and celebrities.

Mexican songstress and actress Lucero wrote on her Twitter account: "What terrible news! Rest in peace ... My deepest condolences for her family and friends." Rivera's colleague on the Mexican show "The Voice of Mexico," pop star Paulina Rubio, said on her Twitter account: "My friend! Why? There is no consolation. God, please help me!"

Born in Long Beach, Calif., Jenni Rivera was at the peak of her career as perhaps the most successful female singer in grupero, a male-dominated regional style influenced by the norteno, cumbia and ranchero styles.

A 43-year-old mother of five children and grandmother of two, the woman known as the "Diva de la Banda" was known for her frank talk about her struggles to give a good life to her children despite a series of setbacks.

She was recently divorced from her third husband, was once detained at a Mexico City airport with tens of thousands of dollars in cash, and she publicly apologized after her brother assaulted a drunken fan who verbally attacked her in 2011.

Her openness about her personal troubles endeared her to millions in the U.S. and Mexico.

"I am the same as the public, as my fans," she told the Associated Press in an interview last March.

Rivera sold 15 million records, and recently won two Billboard Mexican Music Awards: Female Artist of the Year and Banda Album of the Year for Joyas prestadas: Banda. She was nominated for Latin Grammys in 2002, 2008 and 2011.

Plane wreckage 'unrecognizable'

"There is nothing recognizable, neither material nor human" in the wreckage found in the state of Nuevo Leon, Transportation and Communications Minister Gerardo Ruiz Esparza said.

Federal policemen at a base set up near the plane crash site in the municipality of Iturbide, Mexico. Singer Jenni Rivera was one of five passengers on the plane that also carried two pilots. (Daniel Becerril/Reuters)

The impact was so powerful that the remains of the plane "are scattered over an area of 250 to 300 metres. It is almost unrecognizable."

Rivera's father told dozens of reporters gathered in front of his Los Angeles-area home that "I believe my daughter's body is unrecognizable."

There were six other people aboard the plane. No cause was given for the plane's crash, but its wreckage was found near the town of Iturbide in Mexico's Sierra Madre Oriental, where the terrain is very rough.

The Learjet 25, number N345MC, took off from Monterrey at 3:30 a.m. local time and was reported missing about 10 minutes later. It was registered to Starwood Management of Las Vegas, Nevada, according to FAA records. It was built in 1969 and had a current registration through 2015.

Also believed aboard the plane were her publicist, Arturo Rivera, her lawyer, makeup artist and the flight crew.

Though drug trafficking was the theme of some of her songs, she was not considered a singer of "narco corridos," or ballads glorifying drug lords like other groups, such as Los Tigres del Norte. She was better known for singing about her troubles in love and disdain for men.

Her parents were Mexicans who had migrated to the United States. Two of her five brothers, Lupillo and Juan Rivera, are also well-known singers of grupero music.

She studied business administration and formally debuted on the music scene in 1995 with the release of her album Chacalosa. Due to its success, she recorded two more independent albums, We Are Rivera and Farewell to Selena, a tribute album to slain singer Selena that helped expand her following.

At the end of the 1990s, Rivera was signed by Sony Music and released two more albums. But widespread success came for her when she joined Fonovisa and released her 2005 album titled Partier, Rebellious and Daring.

Besides being a singer, she is also a businesswoman and actress, appearing in the indie film Filly Brown, which was shown at the Sundance Film Festival, as the incarcerated mother of Filly Brown.

Performed at concert

On Saturday night, Rivera had given a concert before thousands of fans in Monterrey. After the concert she gave a press conference during which she spoke of her emotional state following her recent divorce from former Major League Baseball pitcher Esteban Loaiza, who played for teams including the New York Yankees and Los Angeles Dodgers.

"I can't get caught up in the negative because that destroys you. Perhaps trying to move away from my problems and focus on the positive is the best I can do. I am a woman like any other and ugly things happen to me like any other woman," she said Saturday night.

"The number of times I have fallen down is the number of times I have gotten up."

Rivera had announced in October that she was divorcing Loaiza after two years of marriage.