Amanda said her uncle is a long-time security guard for the building, and was attacked by a skateboarder. She's seen the surveillance video.
"Something happens and they just surround him and you can see the attack," Jansen said.
RELATED: Security guard working outside former Bank of America Center in SF critically hurt in attack
Jansen told ABC7 News the assault caused brain bleeding, which forced doctors remove almost half of her uncle's skull and part of his brain. He was in a coma up until about a week ago.
"It's hard because he looks scared and I just don't know if he knows what's going on and if he knows that people are around him," she said.
#EXCLUSIVE: Tonight I talked with the niece of a security guard who says her uncle was attacked by a skate boarder while on the job. He had part of his skull and brain removed following the assault. Hear her story at 11 @abc7newsbayarea pic.twitter.com/ssQfPncLwh— Jobina Fortson (@JobinaFortson) December 17, 2018
Police made an arrest in the case. When asked if she had any words for the suspect Amanda replied, "No, yeah I don't."
What led things to get so out of control? Jansen wishes she knew.
"What I'm told is that my uncle had the gift of gab, so he was often dispatched when they did have skaters out there because he did have this easy going nature," she said.
Dan Jansen is an avid fisher and family man, according to his niece.
"He is such a wonderful person and such a jolly sort of man," she said.
The Jansens hope at this point, they can have just some Dan's traits back.