The death of Mexican-American singer Jenni Rivera, 43, Sunday came as a shock to her millions of fans and fellow singers. On Monday more details about the tragic plane crash where she was killed  continued to surface.

Mexican authorities were searching for the bodies of the singer and the other six passengers, including two pilots, who were traveling on Rivera's Learjet. They estimate the search will conclude until Tuesday, according to Mexican reports.

Authorities are also searching the plane's black box to help in their investigation.

The cause of the plane crash remains unclear. Mexico's authorities said the airplane descended abruptly from 35,000 ft to 9,000 feet before it crashed in Nuevo Leon, Mexico.

According to Nuevo Leon's government, Rivera's plane disappeared from the radar 62 miles from the city of Monterrey at about 4:30 am EST Sunday.

"Unfortunately, for authorities, we cannot speculate, we base our investigations in facts, we registered an abrupt descent from 35 thousand feet to nine feet, I don't have more data that I can provide," Alejandro Argudin from Mexico's Secretary of Communications and Transportation told El Universal newspaper.

Near the crash place, authorities found several belongings of the singer such as her driver's license, clothing, boots and accessories such as wigs.

Celebrities and Rivera's own son poured in their condolences for the singer on Twitter.

"I love you mommy. Please, take care of my daddy up there in heaven," her son Johnny Lopez wrote.

"Friend, Why? There is no comfort. My God help me!" tweeted Mexican singer Paulina Rubio who along with Rivera, judged singers in Mexico's TV singing competition "La Voz," the Mexican version of NBC's "The Voice."

"My God! I just found out about the terrible news about Jenny Rivera. I'm praying for a miracle. Prayer chain for Jenny and her family," wrote Thalia.

"My sorrow of a mother, daughter, sister and friend are with you my Jenny. I will never forget your support when I needed you, my dear friend. I bless you always," singer Ana Barbara wrote.

Rivera was born in California to Mexican immigrants. She sold some 15 million records and was known as "The Diva of Banda," for the musical style she was mostly known.

She is survived by her five children:Janney, Jacqueline and Michael, from her first marriage to Jose Trinidad Marin, and Jenicka and Johnny, from her second marriage to Juan Lopez.