Updated at 5:45 p.m. to include suspect's identities.

Two people are in custody after they attacked a valet Sunday morning in downtown Dallas and stole a Lamborghin, police say.

William Caston, 18, and Dez Montayevian Bell, 19, assaulted the valet about 7:45 a.m. in the 500 block of South Lamar Street near the Omni Dallas Hotel and took off in the luxury car.

A police helicopter spotted the car at Kiest Boulevard and Polk Street in central Oak Cliff and tracked it with help from the Dallas County Sheriff's Department.

The Lamborghini caught fire and became disabled in the area near eastbound Interstate 20 and northbound Interstate 45, police said.

Caston is facing theft and robbery charges. Bell is facing charges of robbery and evading in a vehicle.