Still no clues as to cause of air crash that killed singer

Investigators in Mexico on Wednesday were still trying to determine the causes of an air crash that killed a popular singer and six others - a tragedy that has sent the entire nation into mourning.

Jenni Rivera, a 43-year-old internationally known banda singer, perished along with other passengers and two crew members after her private Learjet went down early Sunday shortly after takeoff from a Monterrey airport. She was traveling to Toluca after a concert.

Investigators said Monday night that they believed that the private plane took a nose dive from about 28,000 feet at speeds of more than 600mph. Mexico's Communications and Transportation Secretary said in a statement Tuesday that there were no adverse weather conditions.

But the daily El Norte de Monterrey reported on its website Wednesday that Captain Miguel Pérez Soto, who was piloting the Learjet, had a license that restricted him from flying at night and required him to follow instrument flight rules (IFR). The newspaper said that investigators had found a document at the crash site issued by the US Federal Aviation Administration (FAA) stating that the 79-year-old Pérez was prohibited from transporting passengers.

Mechanical problems

Meanwhile, the Mexico City daily El Universal also reported Wednesday that the same Learjet suffered mechanical failures seven years ago in Amarillo, Texas.

US investigators from the National Transportation Safety Board (NTSB) were also taking part in the investigation.

Meanwhile, hundreds of mourners held a service for Rivera at Monterrey's Virgin de Guadalupe church on Wednesday, the feast day of Mexico's patroness. Other services were scheduled for later this week in Mexico City.

Rivera was one of the most popular singers of banda - a lively polka-style music popular in Northern Mexico and among Mexican immigrants in the United States.

Rivera sold more than 15 million records and was nominated for the Latin Grammys on three occasions. Her reality show I love Jenni was popular with viewers, who enjoyed her outspoken remarks.

Rivera, who was born in Long Beach, California and lived in Encino, was scheduled to appear as a judge in the Mexican version of talent show The Voice next month.