Caltrain officials opened up for the first time about what happened that night. They say a preliminary report shows their officers acted appropriately and followed protocol.
It was clear to those on board the southbound Caltrain on April 1 a man in an orange sweatshirt was out of control.
On the YouTube video, one bystander says "It wasn't safe for one officer to go at him. That guy was really aggressive."
That safety concern is why Caltrain officials are now saying a transit police deputy had no other choice but to Tase the 29-year-old passenger.
"He was pounding on windows, he was racing up and down, he was acting in a very threatening manner," says Caltrain Spokesperson Mark Simon.
"He was a calm passenger at first. Yes, absolutely," says Caltrain passenger Tim Squire.
Squire remembers things very differently. He says the man in orange is a Marine and was simply trying to help him and his girlfriend. Squire claims conductors aggressively and unnecessarily threw the couple off the train and the Marine didn't like what he saw.
"I feel bad, most definitely for the gentleman, because it was in our defense he got up. But if anybody's at fault it's San Mateo County Sheriff because they were using excessive force," says Squire.
"The deputy acted appropriately, but there will be a more thorough investigation," says Simon.
The San Mateo County Sheriff's Department supplies deputies to serve as transit officers. Witnesses say the 29-year-old was Tased at least five times. The first time, the deputy missed and the Taser grazed an innocent bystander.
In a video, that passenger showed officers his arm. He declined medical care.
Caltrain insists Taser procedures were followed, but specific protocol about firing Tasers in confined spaces does not exist.
"These are judgment calls. One of the questions we'll be asking is if the deputy showed the appropriate judgment," says Simon.
"They really needed to work on protocol and how they took that call and how they acted," says Squire.
ABC7 was told the man in the orange sweat shirt was held temporarily for a psychological evaluation and that all of the officers involved in the altercation that night are still on active duty.