Prosecutors said in their motion that Brent failed a urine test taken after a May 24 court hearing in which they had sought for his bond to be revoked due to problems with his alcohol monitoring. While the judge declined to do so, he did order Brent to provide a urine sample.
A hearing on the prosecutors' motion had not been scheduled Thursday afternoon. Brent's attorney, George Milner, did not immediately return a phone message and a spokeswoman for the Dallas County district attorney declined to comment.
Brent is required to wear an alcohol ankle monitor and appear for regular meetings with a county officer. Judge Robert Burns last month ordered a second form of monitoring to take breath samples, and for Brent to provide the sample after the hearing.
The prosecutors' motion said the test results indicate Brent took marijuana within 30 days of the test date and it did not appear the exposure to marijuana was second-hand.
"Given the defendant's prior alcohol-related contacts and the severity of the charge in this case, it is the State's belief that the defendant continues to pose a threat to the community," prosecutors said in the motion.
A crash report released by suburban Dallas police says Brent was driving the night of the crash with a suspended driver's license from Illinois, where he pleaded guilty four years ago to a misdemeanor driving under the influence charge. Brent and Brown both played college football at Illinois.
Brent faces up to 20 years in prison if convicted of intoxication manslaughter, though he could also get probation.