A US Army Sergeant who fatally shot an armed protester at a Black Lives Matter march in Texas has been sentenced to 25 years in prison, after prosecutors used his social media history and text messages to portray him as a racist who may commit violence again.

Daniel Perry’s sentence now pushes the case toward a potentially thorny decision for Republican Texas Governor Greg Abbott, who has said he wants to issue a swift pardon.

Abbott requested the state Board of Pardons and Paroles to send him a pardon recommendation for Perry shortly after he was convicted in April of killing Garrett Foster at the Austin march in July 2020.

Abbott lauded Texas’ tough Stand Your Ground self-defence laws and said Perry was railroaded by a liberal prosecutor. Since then, Perry’s trail of texts and online posts, including shockingly racist images, have been made public and the governor has stayed silent on the matter.

US Army Sergeant Daniel Perry. Photo / AP

Abbott’s office did not respond to an Associated Press request for comment on the sentence or whether he still intends to issue a pardon. Perry, 36, could have received up to life in prison.

Rice University political science professor Mark Jones said Abbott moved too soon on the call for a pardon.

“Abbott clearly boxed himself into a corner,” when he appeared to respond to criticism from conservative former Fox News star Tucker Carlson, who demanded the governor act, Jones said.

“I suspect if Governor Abbott had known all that he knows now, he would not have jumped the gun on pledging to pardon him,” Jones said.

The Pardons and Parole board, which is appointed by Abbott, has already started reviewing Perry’s case. State law requires the board to recommend a pardon before the governor can act.

The case has been embroiled in politics as it came amid widespread demonstrations against police killings and racial injustice, following the killing of George Floyd, a black man, by a white Minneapolis police officer.

This image from video shows former Minneapolis Police Officers Thomas Lane (left) and J Alexander Kueng escorting George Floyd to a police vehicle outside. Photo / AP

Perry’s attorneys called the case a “political prosecution” and the release of the texts and social media posts “character assassination”.

Attorney Clinton Broden said the defence team would pursue both a pardon and a standard appeal in the court system.

“Those who claim that Governor Abbott’s expressed intent is based on politics simply choose to ignore the fact that it was only the political machinations of a rogue district attorney which led to Sergeant Perry’s prosecution,” he said.

Travis County District Attorney Jose Garza said it was Abbott “who decided to insert politics in this case”. Garza said he’s been assured by the parole board that he and Foster’s family will be given a chance to address the board in Perry’s case.

In a statement, the board confirmed the investigation is ongoing and declined further comment.

“The entire history of the board, the board has been a careful steward of the power of clemency in this state,” Garza said. “Our criminal justice system is not perfect, but in this case it worked exactly as it should. The Travis County District Attorney’s office is not done fighting for Garrett and the integrity of that process here.”

Whitney Mitchell, the partner of Garrett Foster, cries as the verdict is read that Daniel Perry is guilty of the killing of Foster. Photo / AP

In a brief statement before sentencing, state District Judge Clifford Brown said Perry received a fair trial. The jury’s verdict “deserves our honour and it deserves to be respected”, Brown said, without mentioning the potential pardon.

Jones predicted the board will let Perry’s legal appeals happen first, and that it would be years, if ever, before the board makes a recommendation in the case.

“The majority (of conservatives) will want to put it in the rearview mirror,” Jones said. “Conservatives have far better causes and individuals to support, far better than Daniel Perry.”

Daniel Perry was convicted of murder for fatally shooting Garrett Foster, an armed protester in 2020. Photo / AP

Perry, who is white, was stationed at Fort Hood, about 110km north of Austin when the shooting happened. He was working as a ride-share driver and had just dropped off a customer when he turned onto a street filled with protesters. Foster, a 28-year-old Air Force veteran who was also white, was legally carrying an AK-47 rifle.

Perry said he acted in self-defence, claiming that he was trying to drive past the crowd and fired his pistol when Foster pointed a rifle at him. Witnesses testified that they did not see Foster raise his weapon, and prosecutors argued that Perry could have driven away without shooting.

Army spokesman Bryce Dubee has said Perry is classified as in “civilian confinement” pending separation from the military.

Among Perry’s statements introduced Tuesday, he wrote on Facebook a month before the shooting: “It is official I am a racist because I do not agree with people acting like animals at the zoo.”

Floyd was killed on May 25, 2020. A few days later as protests erupted, Perry sent a text message to an acquaintance: “I might go to Dallas to shoot looters.”

Foster was with his girlfriend, Whitney Mitchell, who is black and uses a wheelchair when Perry gunned him down. Mitchell and several members of Foster’s family were in the courtroom for sentencing Wednesday.

Foster’s mother, Sheila Foster, was allowed to address Perry after he was sentenced and still in the courtroom.

“After three long years we’re finally getting justice for Garrett,” she said. “Mr Perry, I pray to God that one day he will get rid of all this hate that is in your heart.”