nbc bay area's unser hudson was first on the scene and officers say the driver went after the group first with an ax, then with a car? >> reporter: yeah, good evening, terry. i spoke with san francisco's attorney general and they said of the four men hospitalized, one is in critical condition, two are said to be in serious condition, and the fourth man in fair condition. now, police are still investigating what led up to the deadly hit-and-run, but they say this is now a homicide investigation. >> got out of the van with an ax and went after the guys, and they just took off their belts and were kind of lashing at him -- >> reporter: this witness, who did not want to be identified, says what began as a fight quickly escalated as the driver mowed down five men on the sidewalk. >> he drove it up on the sidewalk full pedal to the metal and drove over four out of the five. >> reporter: this witness says the driver swung an ax at the group but was chased off. he then allegedly came back and attacked the men with his van as they tried to walk away. >> the police arrived within minutes. all four