The Arlington Police Department announced the arrest of a man they say targeted his ex in a shooting on an Arlington highway, killing her and her unborn baby.

A U.S. Marshals task force arrested 29-year-old Malik Miner in Midlothian on Wednesday. He is charged with one count of capital murder, three counts  of aggravated assault with a deadly weapon and one count of deadly conduct.

The victim, 29-year-old Bre'Asia Johnson, died on November 12. Police said she was a passenger in a vehicle that was driving in the westbound lanes of I-20 near Bowman Springs Road when Miner opened fire.

Johnson's 28-year-old boyfriend, who was behind the wheel, was also hit but managed to pull off to a nearby gas station and call 911. 

Officers found Johnson unresponsive, APD said. She was taken to a hospital where she was pronounced dead. The driver was hospitalized from his injuries. 

Two children were also in the vehicle; Johnson's relatives told CBS News Texas said she shielded them, even though they were not her own. The children were not seriously injured.

A second, unrelated vehicle was also hit by gunshots, but no one inside was hurt.

Police: Investigation reveals suspect followed victims

Arlington police said in a news release Thursday morning that detectives learned in their investigation that Miner and Johnson were previously in a romantic relationship, and that Miner was in a feud with her current boyfriend.

Police said detectives obtained a search warrant and went through Miner's cell phone, which showed that Miner and Johnson's boyfriend had previous communications. Phone records not only placed Miner at the scene of the shooting, but showed that "his movements were nearly identical to Ms. Johnson's movements in the minutes leading up to the shooting," police said, indicating that Minor was following the victims' vehicle.

As of Thursday morning, Miner was in custody at the Arlington jail.