Police say a 75-year-old man died of a heart attack after getting into an altercation with a woman over a seat on a San Francisco bus.
San Francisco police say they have launched a suspicious death and assault investigation following the Thursday incident.
Officer Giselle Talkoff tells the San Francisco Chronicle the man, whose name was being withheld by the medical examiner's office pending notification of his relatives, died while on a Muni bus at Kearny at Geary streets.
She says the man went into cardiac arrest and died just moments after getting into an argument with a 53-year-old woman over a seat on another bus.
Talkoff says the incident remains under investigation and no arrests have been made.