The disturbing video was shot at TyCalK9 Dog Training Center in Arcola, Texas, according to ABC13.
In the video, which has been widely circulated on social media, the trainer picks the German Shepherd dog up by its leash before swinging it over his shoulder and pounding it to the ground.
The young dog can be heard on the video whimpering in distress as it tries to get to its feet following the incident.
Now the Fort Bend County District Attorney’s Office has confirmed it is probing what happened.
“The District Attorney’s Office is actively investigating an animal cruelty report regarding a video on social media depicting the alleged mistreatment of a dog in Fort Bend County,” the office said in a statement.
“We cannot share the details as the investigation is ongoing, but we take these matters seriously and do not condone the mistreatment of animals in any regard.
“A thorough investigation by experienced animal cruelty investigators and prosecutors is underway.”
The Houston SPCA has also offered its assistance into the investigation, says the news station.
On its website, which now appears to have been taken offline, TyCalK9 says it trains dogs for celebrity clients including NBA and reality TV stars.
The training facility’s Instagram page also appears to have been removed.