The newly-released photo shows Martin, wearing a green wig, smiling. In fact, everyone looks happy. But police say moments later it turned ugly.
"At approximately 5 p.m. there was a confrontation between Martin's group and another group consisting of about 12 women and men," John Loftus with the San Francisco Police Department said.
Three of those 12 men and women appear in the photo on the left; a woman wearing an orange tutu and sunglasses, a man wearing a 49ers jersey, and the other a black cap. Police say they are part of the group that had a confrontation with Martin's group. The men had 49er jerseys and the women tutus. They had participated earlier in the Bay to Breakers race.
"If you think you have a picture that may be at all helpful to us please send it along, video also, anything that anybody has that they think might be useful, we'll take it," SFPD Chief Greg Suhr said.
One of the men has a tattoo on his neck. Police say the gang task force has been involved in the investigation. Police also believe they know how the argument started.
"There was an argument over a cellphone, a dispute over a cellphone," Loftus said.
Police also distributed video of people who were in the park just about the time the altercation occurred.
The incident happened on May 20. Martin was punched and his head hit the pavement. He was sent to the hospital but never recovered. He was taken off life support and died on Friday.
If you have any information regarding this case, call SFPD at (415) 553-1145 or contact their tip line at (415) 575-4444. You can also send a text to TIP411.