Police think it was teenagers who attacked the elderly man almost two years ago as he was walking home, but they don't know how many of them there were or why they would do such a thing. They're hoping a reminder and a reward will bring them the answers they need.
"Basically, at this point, I have nothing," said police inspector Kevin Jones.
San Francisco police have no leads in the fatal beating of the 83-year-old Bayview resident. Chen was killed almost two years ago.
"He was walking home from, getting off of Muni, walking back down Oakdale towards his home when he was approached and attacked by a group of unknown youths," said Jones.
It happened near 3rd Street.
"Mr. Chen fell to the ground, hit his head and sustained serious enough injuries where he eventually a few days later went to the hospital and he succumbed to those injuries approx a month and a half later," said Jones.
"That's sad, you know for anyone, especially an older gentleman like this. You're supposed to be enjoying your golden years, not worrying about if he going to make it from one block to the next," said Panorea Rommel, a Bayview resident.
With no surveillance of the crime or those responsible, police are now passing out fliers to people in the neighborhood. In addition to reminding the community about Chen's death, police are hoping a 100 thousand dollar reward will also spark some new information.
"This was issued by then-Mayor Gavin Newsom back in 2010 after the incident occurred," said Jones.
But money may not be enough for Milton Johnson who says he works with at-risk youth.
"I'd just stay out of it... because it's not my business," said Johnson. That's the attitude police are worried about, but they say they have had cases where someone decides to come forward years down the line.
"Their circumstances change and they feel more comfortable in coming forward and providing information," said Jones.
They're hoping that will be the case again this time.
"There's always people down here and there's also residents here along the area and so far we've had no luck. It could be a situation where there was no one who really observed it, but I believe that there probably was," said Jones.
Police say there was no indication this was a robbery and they don't believe race was a motivation. What they do know is that this case needs to be closed and the community may be their only hope.