Police cordoned off a city street in an investigation of the death of a seven-year-old boy who was struck and killed by a car near Central Square last week.

Joshua DaSilva of Reading was rushed to Cambridge Hospital with severe head and body injuries just after 7 p.m. last Tuesday.

He was hit by Darla Pires, 20, of Everett and pronounced dead at 8 p.m. that night.

Witnesses interviewed yesterday said DaSilva rushed out across the street into the path of pires' green Geo tracker.

According to Cambridge Police spokesperson Frank T. Pasquarello, DaSliva was visiting his grandmother when the accident occurred outside her house on Columbia St., off Cambridge St.

The young boy was playing outside with his 11-year-old sister at the time of the accident, Pasquarello said.

The driver of the car was very upset about the incident, according to Pasquarello.

"She was very shaken up, as you can imaging," he said.

"It was very traumatic for everyone I could see at the hospital," Pasquarello said. "Everyone was hoping against hope they would be able to save him."

Last night, Cambridge police closed down Columbia St. to conduct a reconstruction of the accident scene.

During the reconstruction, state police and Cambridge police accident investigators drove Pires' car down the street several times.

According to Pasquarello, police attempted to calculate the exact speed of the car at the time of the accident and determine if there were any obstacles blocking the driver's view.

Police also took several dozen photographs of the accident scene and the car.

No charges have been filed against Pires, and the investigation is continuing, Pasquarello said.

"We want to take our time to make sure there are no mistakes," the police spokesperson said last night.

Efforts to reach DaSilva's family last night were unsuccessful.