Selena Quintanilla's Dad Abraham Dead at 86

Abraham Isaac Quintanilla Jr., the father of the late Tejano music icon Selena, has died.

His son, A.B. Quintanilla III, shared the shocking news on Instagram Saturday morning, sharing a photo of his dad and writing ... "It’s with a heavy heart to let you guys know that my Dad passed away today."

The cause of death was not immediately shared. The Nueces County Medical Examiner tells TMZ ... they got notification of his death this morning and did not accept jurisdiction, meaning there is no investigation into his death because there is no suspicion of trauma, foul play or something that would raise an alarm about his passing. The body has been released to a funeral home, we're told.

The medical examiner could not confirm the date of his death. We have reached out to the Quintanilla family for comment ... so far, no word back.

Fans are well aware Quintanilla Jr. was a huge influence in Selena’s life and career, serving as her manager and then as a safeguard for the memory of her legacy after she was murdered in March 1995 by Yolanda Saldívar, the president of her fan club.

Quintanilla Jr. once said he's the "opposite" of his trustworthy daughter, telling New York Daily News in 2015 ...  "I was raised in the streets when I was young so I’m always suspicious of everything. My kids were not raised that way because they were under my wing and I protected them.  ... I used to worry about Selena being so trusting."

He said during the same interview he thought Selena may have had "three or four or five kids" if she were still alive because "she loved children." She was married to Chris Pérez at the time of her death.

Quintanilla Jr. spoke about the first time he brought the "Bidi Bidi Bom Bom" hitmaker to a record label in San Antonio in the new Netflix documentary "Selena y Los Dinos," recalling ... "At first, they were skeptical because it’s a girl -- and a young girl. I said, 'Well, let’s give it a try one time,' and we recorded a song." She was signed immediately, and the rest was history.

Abraham was married to Marcella Quintanilla, and is also survived by their daughter, Suzette Quintanilla.

He was 86.