WATERTOWN — In a spasm of violence at a major intersection here, a tow truck struck and killed a woman as she tried to cross Route 16 and a man believed to be her son allegedly stabbed the driver five times while shouting “You killed my mom!”
The encounter, at Route 16 and Galen Street around 11:20 a.m. Wednesday, unfolded in full view of people waiting at an MBTA bus stop near the border with Newton.
Carlos Gonzalez-Moreno said he was waiting to board a T bus when he saw the truck stop — and stay there, even though other drivers began blowing their horns in apparent frustration.
Gonzalez-Moreno, a 19-year-old Suffolk University student, told the Globe he heard someone shout, “You killed my mom!” as that person got into a scuffle with the driver of the tow truck.
Middlesex District Attorney Marian T. Ryan, whose office is helping to investigate the incident, said at a press conference Watertown police responded to a 911 call for a road-rage incident. She said the woman who was struck was pronounced dead at the scene.
Relatives identified her as Benita Horner, 68, and the man who allegedly stabbed the driver as her son, Philip. The two were described as very close, sharing an apartment in a complex for seniors in Belmont.
The district attorney’s office declined to confirm either identity Wednesday night.
Ryan said the suspect stabbed the tow-truck driver approximately five times in the torso. The driver was in critical condition in a Boston hospital, she said.
Ryan said the suspect, in police custody, was taken to a hospital. She would not say what prompted the man’s hospitalization. The incident is under investigation by Watertown and State Police, she said.
The violence stunned witnesses in a busy corner of Watertown.
“The son went crazy,” said Zeidan Taha, the manager at Watertown Taxi, who was among the first to call police.
Taha said the woman was crossing the street with her son when she was run over by the tow truck and suffered a catastrophic head injury.
The son was furious, screaming in the street, Taha said. He confronted the tow-truck driver with a knife, he said.
“The guy kept stabbing him and chasing him all over, around the truck,” said Taha, adding the victim suffered wounds in the stomach and back.
The driver repeatedly told the angry man, “I didn’t see her! I didn’t see her!,” he said.
Sheryl Leonard, who is Benita Horner’s stepdaughter, described her as a doting mother and grandmother.
“She really loved her son,’’ she said. “I can’t imagine him seeing what happened to her today.”
Growing up in Watertown, Leonard recalled Horner’s love of cooking. Pepper steak and fried chicken were among the culinary highlights, she said.
“She was a great cook,” she said.
Leonard, 53, now lives in Maryland, where she is raising Philip’s son.
Mark Horner, Philip’s half-brother and Benita’s stepson, said Benita’s priority in recent years was talking care of Philip. Horner, who lives in North Attleborough, said he had not seen Benita in about five years.
“It’s a sad thing,” the North Attleborough resident said over the phone on Wednesday night. “We feel bad for the tow truck driver and his family. Hopefully he makes it.”
Portions of Route 16 — also known as Watertown Street — were closed while police investigated. Horner’s body, which appeared to have landed underneath the wheels of the truck, was covered with a white sheet.
Yellow police tape was strung up around the intersection and yellow evidence markers dotted the sidewalk. One was placed next to what appeared to be blood stains.
“This was a bad scene over here,” Watertown Police Chief Michael Lawn said.
John R. Ellement and Travis Andersen of the Globe Staff and Globe correspondent Andres Picon contributed to this report.