MELBOURNE, Fla. -- A Brevard County school bus driver who was arrested for allegedly threatening to attack a student's mother was caught on camera urinating in a bus, according to investigators.

Investigators were reviewing surveillance video from a bus used by Gemini Elementary School students. Last week, they had arrested Alcide Pierre-Louis and charged him with aggravated assault for threatening a student's mother.

The tape showed Pierre-Louis yelling "Come inside, I'll beat you up. Come inside, I'll beat you up."

But Melbourne investigators also say that same camera caught Pierre-Louis urinating into a plastic bottle while sitting among the rows of seats used by his students. In a videotape sealed into evidence, investigators say the driver can be seen emptying that bottle out the bus' back door.

Pierre bailed out of jail on the aggravated assault charge but not one answered the door at his home.

A Brevard County School District a spokesperson said he had not heard of what he called the "very unusual" behavior and that it would be investigated.

The district is already reviewing its driver's arrest. Police say besides yelling at the mother, Pierre-Louis also waved a three foot pipe and repeatedly threatened to beat Muneerah Ali, the mother of an 11-year-old student.

Nearly a dozen elementary school students witnessed the argument, which began after Ali confronted the driver over leaving her son at his bus stop.

The district has transferred Pierre-Louis away from children pending the outcome of their investigation. Starting Monday, he will be washing the school buses he used to drive.

Pierre-Louis has never been written up by the school district and has no criminal record in Florida.