PHOENIX – A boxer’s death hours after his undercard loss Saturday night is under investigation by Arizona authorities.

Pedro Rodriguez, a 37-year-old junior-featherweight from the Mexican state of Durango, was found dead early Sunday, the morning after a loss by unanimous decision to Phillip Vella in a six-round bout at the American Royal Palace in north Phoenix. 

As of Tuesday, there was no official cause of death.

Del Sol Boxing Promotions, which promoted the fight card, released a formal statement:

“We are deeply saddened by the passing of Pedro Rodriguez. Our thoughts are with his family, loved ones and team during this incredibly difficult time.”

People who saw the fight from ringside told BoxingScene they never saw Rodriguez (15-26-3) get seriously hurt. He was not knocked down. He walked out of the ring and out of the arena under his own power.

“There has been speculation regarding the cause of his death,” the Del Sol Boxing statement continued. “While we understand the public's concern, we want to be clear: at this time, no official cause of death has been determined. The local authorities are investigating and we are fully cooperating with them. We are also in close communication with Pedro’s family, and, out of respect for them, we will not rush to judgement or contribute to public speculation.

“Pedro was not just a fighter — he was a father, son, a grandson and a man. We ask everyone to allow space for his family to grieve and for the truth to come out through proper channels.”

After the fight, a ringside source told BoxingScene that Rodriguez received and replied to a text message, telling him to be ready to leave for Sky Harbor International Airport at 4 a.m. Sunday.

When it was time to leave for the Phoenix airport, sources told BoxingScene that people with him tried to awaken him, but there was no response.

That’s when hotel staff unlocked his door and saw he was “lifeless,” according to one official. Then, the police were called and declared Rodriguez dead, sources said.

“There is a time for compassion, not speculation. We ask everyone to honor Pedro’s memory with dignity and care. We will share additional information appropriately,’’ Del Sol Boxing wrote.

Vella (4-0), of Las Vegas, responded to reports of Rodriguez’ death on Instagram, saying: “Truly heartbroken to find out this news. Thankful to have shared the ring with Pedro for six rounds.

"My thoughts and prayers are with his family. Rest easy, champion."