Jenni Rivera was declared dead by American officials after a plane carrying the Mexican-American singer crashed Sunday in Mexico.

But her family seems unwilling to believe that she has really died, and Rivera's brother, Juan, spoke out Monday on his family's enduring hopes that the star survived the crash, Reuters reported.

“In our eyes, we still have faith that our sister will be OK," Juan told reporters outside the Riveras' Long Beach, Calif., home on Monday. “We thank God for the life that he has given ... my sister … for all the triumphs and successes she has had, and we expect that there will be more in the future.”

Rivera was killed on Sunday in a small aircraft crash in northern Mexico, according to American officials. And her father, Pedro, told Telemundo TV that everyone on the plane had died, which jives with the ongoing status as reported by officials, Reuters said.

The UK's Daily Mail reports that the evidence does not point to her having survived the crash, however, as her driver's license was found “half-melted” at the scene of the crash.

And Mexico's Transportation and Communication Minister Gerardo Ruiz Esparza told Televisa TV that the crash was catastrophic, adding credence to the assertion that Rivera did not survive.

“There is nothing recognizable, neither material nor human in the wreckage,” he said, according to the Daily Mail.

Juan also took to Twitter in Spanish to broadcast his family's belief that their beloved Jenni, 43, is still living:

“My sister is still ALIVE! Until I have her body in my hands I will keep saying she LIVES. NOTHING has been CONFIRMED YET,” Global Grind translated.

And Rivera's youngest son, 11-year-old Johnny Angel Lopez, is apparently also holding out hope, according to a Monday Twitter posting quoted by Global Grind:

“My Mama is alive … I may have posted a photo. I lost hope but I got it back. She is not dead.”

The investigation into the crash of the private Learjet by the National Transportation Safety Board in the United States and Mexican officials is ongoing, Reuters reported.

The plane went down at about 4:30 a.m. Eastern Standard Time in Iturbide, about 70 miles south of Monterrey. It was headed to Mexico City and carried Rivera and six other people, including her lawyer and publicist, according to the Daily Mail.

There has been no conclusion yet as to what caused the crash, which has broken the hearts of many fans of Rivera, who was a major player in Mexico's folk nortena and banda genres and sold more than 15 million albums in her lengthy career. But Global Grind reports that the plane had a fuel system malfunction seven years ago that caused it to crash while trying to take off from an airstrip in Texas.

“The entire Universal Music Group family is deeply saddened by the sudden loss of our dear friend Jenni Rivera," her record label said in a statement after her death was announced, Reuters said. “From her incredibly versatile talent to the way she embraced her fans around the world, Jenni was simply incomparable. ... Her talent will be missed, but her gift of music will be with us always.”