EDINBURG - An investigation into the death of an inmate who was found unresponsive at the state jail in Edinburg is underway.

Authorities said 27-year-old Joshua Denn died of natural causes last Sunday. He was just one month into his 4-year sentence for arson, and 1-year sentence for unauthorized use of a motor vehicle at the Lopez State Jail in Edinburg.

His family said they don’t understand how it could have happened. Sara Denn, Joshua’s sister, said her family was getting conflicting stories from state officials about what happened to her brother the night of his death.

Denn said they first heard that Joshua was found dead in his cell. She said they received another account moments later.

“My dad called back and they said that they found him having trouble breathing so they called 911,” she said.

Texas Department of Criminal Justice spokesperson Robert Durst said all TDCJ units have trained medical personnel. He said it appears the inmate had died of natural causes.

However, Denn said his brother was physically active at the jail.

“He exercised, did pushups, sit ups, jumping jacks, he ran and he went to the gym. He’s not somebody who is going to flip over and stop breathing,” she said.

Denn said all she and her family want are answers before their last good bye.

The state said an autopsy will be performed by the Harris County medical examiner in Houston.

CHANNEL 5 NEWS was able to speak with Joshua’s wife. She said the family will be ordering an independent autopsy.