Irving police spokesman John Argumaniz said the accident happened about 2:20 a.m. Saturday in the Dallas suburb, hours before Brent was to be on a team flight to Cincinnati for the Cowboys' game Sunday against the Bengals.
Argumaniz said the 25-year-old Brown -- a practice-squad linebacker who also was Brent's teammate at the University of Illinois for three seasons -- was found unresponsive at the scene and pronounced dead at a hospital.
"We are deeply saddened by the news of this accident and the passing of Jerry Brown," Cowboys owner Jerry Jones said in a statement. "At this time, our hearts and prayers and deepest sympathies are with the members of Jerry's family and all of those who knew him and loved him."
Officers conducted a field sobriety test on Brent and arrested him on suspicion of driving while intoxicated, Argumaniz said. The charge, a second-degree felony punishable by two to 20 years in prison, was upgraded after Brown was pronounced dead.
Argumaniz said Brent, who pleaded guilty to a drunken driving charge three years ago at Illinois, was being held without bond. Brent is named as Joshua Price-Brent in the police news release. Argumaniz said Brent missed a 10 a.m. Saturday booking session with a judge because he was intoxicated. He did not know if Brent had an attorney.
Brent was speeding when the vehicle hit a curb and flipped at least once, Argumaniz said. Police received 911 calls from motorists who saw the upside-down vehicle but they did not immediately have any eyewitnesses to the wreck, the police spokesman said.
Argumaniz said when officers arrived at the scene on a state highway service road, Brent was dragging Brown from the vehicle, a Mercedes, which was on fire. Officers quickly put out the small blaze, he said.
Argumaniz wasn't sure if the vehicle was a car or SUV and said it wasn't known how fast the vehicle was traveling. The road has a 45 mph limit.
"I can say investigators are certain they were traveling well above the posted speed limit," Argumaniz said.
Before he was taken to the jail, Brent went to a hospital for a blood draw for alcohol testing and also received treatment for some minor scrapes.
Argumaniz said Brent identified himself to officers as a Cowboys player.
Brent was arrested in February 2009 near the Illinois campus for driving under the influence, driving on a suspended license and speeding, according to Champaign County, Ill., court records.
In June 2009, Brent pleaded guilty to DUI and was sentenced to 60 days in jail, two years of probation, 200 hours of community service and a fine of about $2,000. As part of his plea deal, prosecutors dropped one count of aggravated DUI/no valid driver's license. Brent successfully completed his probation in July 2011, court records show.
Brent, a nose guard, has played in all 12 games this season and has been a bigger presence on defense with starter Jay Ratliff battling injuries. Brent made his first career start in the season opener against the New York Giants and has 35 tackles and 1 1/2 sacks.
The Cowboys signed Brown to their practice squad Oct. 24, but he hasn't been on the active roster. He was released from the Indianapolis Colts' practice squad Oct. 20. Brown played in one game for the Colts, a loss to the New York Jets on Oct. 14.
"On behalf of the entire Colts family, our sincerest condolences go out to Jerry's family and friends," Colts general manager Ryan Grigson said in a statement. "He was a good teammate that was well liked by all. Today's tragic news is just another reminder of how fragile life is and how everyday given is a gift."
Brent and Brown played at Illinois from 2007 to 2009. Brent played as a freshman and finished his career with 71 tackles and five sacks. Shortly after his guilty plea on the DUI charge, Brent entered the supplemental draft with a year of eligibility remaining, and the Cowboys took him in the seventh round.
Brown, who took a redshirt season at Illinois the year before Brent arrived, had 13 tackles combined in 2007 and 2008 but didn't play in 2009.
"I can't believe it," Travon Bellamy, a former Illinois teammate, wrote on Twitter. "Before people pass judgment on Josh, they need to know that he is a good person that made a bad mistake."
Brown played for San Antonio in the Arena Football League this year. In 2011, he played for Jacksonville in the AFL and the Hamilton Tiger-Cats in the Canadian Football League.
He was born and grew up in St. Louis, attending Vashon High School.