SAN ANTONIO -

Three law enforcement agencies are searching for a teenaged robbery suspect who escaped from a detention officer Thursday afternoon.

The 16-year-old was being transported in handcuffs and leg shackles by the Texas Juvenile Justice Department from Edinburg to Mart, near Waco.

But near downtown San Antonio, the teen told his driver he was getting sick.

The detention officer pulled over to let the teen throw up, but instead, he ran away.

He crawled through a hole in a fence and jumped onto a slow-moving train.

That train stopped a short time later near Interstate 35 and Splashtown, but the teen wasn't on it.

Officers from the San Antonio Police Department, the Department of Public Safety and the Texas Juvenile Justice Department are searching the area with dogs.

But as of Thursday afternoon, he had not been located.