Nawindra "Mike" Singh told his friends that he bumped into another man as he was exiting the Powell Street station on his way to work at about 7 a.m. on April 5, Burlingame police Capt. Mike Matteucci said Wednesday.
Based on witness accounts and statements from his friends, police believe Singh and the suspect got into a physical fight, during which Singh was punched or pushed and hit his head on a wall or the ground, Matteucci said.
Singh refused medical attention at the scene, police said.
Over the next three days, Singh complained growing pain from hitting his head, police said.
The last time Singh made contact with his friends was at 12:30 p.m. on Sunday, April 8, Matteucci said.
Police went to his apartment in the 800 block of Winchester Drive at about 5:40 p.m. that day to perform a welfare check, and found him dead on the living room floor.
The San Mateo County coroner's office confirmed that Singh died of head trauma, Matteucci said.
Investigators are hoping additional witnesses will come forward with information about the other person involved in the fight.
Anyone who might have witnessed the incident outside the BART station or who has information about a potential suspect is asked to call Burlingame police at (650) 777-4100.