The family of a Texas State University freshman, who was allegedly shot dead by a sheriff's deputy, has revealed what they say were his tragic final minutes before he was killed.

John Mendoza Jr, 18, died on June 1 when Brazoria County Sheriff's Department Deputy Kevin Tippit allegedly shot him following an attempted traffic stop.

The teen had spent the evening with three friends at a park in Lake Jackson, around 55 miles south of Houston. Tippit followed them in his vehicle and eventually tried to pull him over.

Authorities claim Mendoza then tried to flee, and led the deputy on a mile-long pursuit to his home, before he was shot in his car when he pulled into his garage. 

But the Mendoza family has come out fighting that narrative, claiming the unarmed teen was mercilessly killed despite having both of his hands up in the officer's view.

They told the Daily Mail through their attorney Charles Adams that he was not trying to evade cops, and that he kept telling his friends he wanted to go and get his dad, who was just a short drive away.  

Demanding Tippit face charges, Adams called Mendoza's death an 'execution.'  

Tippit was sensationally fired by the force and branded a disgrace by the sheriff.  

Mendoza's family said he was home for the summer from his freshman year at Texas State when he was killed. They said he had hopes of playing for the college football team after being a standout high school player.

Adams said the incident unfolded when Tippit followed Mendoza and three of his friends from a park, adding that the deputy followed them before eventually turning on his sirens. 

While admitting that Mendoza did not stop, he said the 18-year-old drove slowly back to his nearby home, remaining below the speed limit despite driving an SRT Dodge Challenger 'capable of great speeds.'

Brazoria County Sheriff Bo Stallman said this week that he had fired Tippit following the shooting, as he condemned Mendoza's death as a 'tragedy.' This came after a two-week investigation.

While authorities say Tippit is still under investigation, Adams said the Mendoza family will not be satisfied until the deputy is 'arrested and charged with murder.' 

Following news of Tippit's firing, Adams said in a statement to the Daily Mail that he was 'encouraged' by the sheriff's decision.

'But it is not the consequence the family needs to start the journey to healing,' the lawyer continued.

'Any other person in Brazoria County that shot an unarmed man on camera would be arrested and charged with murder. That is what John's family is seeking. 

'Thank you to everyone who has supported the memory and legacy of John and the Mendoza family throughout this very difficult time. Please keep demanding justice.' 

Mendoza was shot once in his car in the garage of his family home – just seven seconds after he stopped the alleged pursuit, Adams said. 

The student was taken to the hospital, where he was pronounced dead.

Adams said all four occupants in the car had their hands up when Tippit opened fire, and alleged that the deputy issued 'no directives or commands' before shooting. 

The attorney added that Mendoza likely wanted his father with him for his interaction with law enforcement because he was 'scared' by Tippit following him, and said he made 'no effort to escape.' The teen was rattled and confused, Adams said.

He added that authorities have not established any reason that Mendoza would have been pulled over in the first place, and said even if the teenager did try to evade the police, the charge does not 'subject a defendant to the death penalty.' 

In the video statement where he announced the firing, Stallman described Mendoza's death as a 'tragedy.'

He said the Texas Rangers were conducting an independent investigation into the shooting, and said the District Attorney's office would determine whether Tippit would face charges.

The sheriff said that while he does not control whether Tippit will be prosecuted, he made his decision 'based on the ongoing investigations and the information available to me.'

The move to fire Tippit within two weeks of the shooting marks a significant punishment from the sheriff's department, with law enforcement officers typically placed on paid administrative leave following an officer-involved incident. 

Stallman said his decision was 'due to the policy violations' and 'the handling and discharging of his firearm' during the traffic stop.

Brazoria County District Attorney Tom Selleck said on June 3 that his office was conducting a 'thorough and comprehensive investigation,' and said the case would be presented to a grand jury to consider charges.

Selleck's office said the process could take several months before evidence is gathered and presented to a grand jury.

Mendoza's family said they were left heartbroken and called for justice for the Texas State freshman.

Mendoza's sister, Allyson, wrote in the description of a GoFundMe campaign that they were fundraising 'to help raise awareness, seek accountability, and honor the life of my little brother.'

Allyson alleged that Tippit had targeted her brother and followed him home from a park before shooting him 'without warning or direction.'

She said paramedics took more than 20 minutes to get to the scene, accusing emergency services of failing to arrive in time to save Mendoza.

'Those lost minutes mattered,' she wrote. 'Where was the sense of urgency?? From the unjustified and aggressive use of force by the officer who shot John, to the delayed emergency response. John was failed at every stage.

'Our family is left with heartbreaking questions.'

Stallman also directly addressed Mendoza's family in his video message. 'John Gabriel Mendoza Jr lost his life, your family lost a son, friends lost someone they loved,' he said.

'Regardless of any outcome of any investigation, your family's loss is permanent and your grief is real.

'I can not begin to understand the pain that your family is experiencing, but I wanted you to know that your loss is seen and that John Mendoza Jr will not be forgotten.'