Charges have been filed against the man accused of stealing an ambulance on Houston's south side Tuesday night.

It started with a call out in the 6600 block of Scott Street around 8:30 p.m. Tuesday.

First responders said they saw a man, identified as Joey Reed, acting erratically when they pulled up to the scene. They said he began to get aggressive so police were called to help. 

As they waited for police, EMTs said Reed, 32, got into the driver's seat of the ambulance and drove away.

With the help of an on-board GPS system, Houston police were able to track the ambulance.

Officers eventually caught up with the rig on Highway 288 and Pearland.

Houston police said they surrounded the ambulance forcing Reed driving the ambulance off the road.

Reed eventually got out of the ambulance.

"That's when he began spitting up white chunks believed to be crack cocaine,"said Lt. Larry Crowson with the Houston Police Department.

Reed was arrested and charged with unauthorized use of a motor vehicle and possession of a controlled substance.

Police said the ambulance suffered two flat tires during the incident.