Authorities are investigating a possible connection between a carload of men, chased to Oakland following an attempted robbery in Lafayette Saturday, and a robbery spree in which two men robbed four pedestrians in Walnut Creek and Lafayette Friday afternoon.

Walnut Creek police were looking for a young gunman in his late teens or early 20s who robbed two people walking in downtown Walnut Creek Friday afternoon.

Contra Costa Sheriff's deputies suspect that man and another were also involved in holdups of pedestrians in unincorporated Walnut Creek's Parkmead neighborhood and in Lafayette late Friday. 

On Saturday, Lafayette police and California Highway Patrol officers pursued a carload of suspected armed robbers from Lafayette to Oakland - arresting three and mounting a widespread neighborhood search for a fourth, according to Lamorinda Patch. 

Witnesses told Lamorinda Patch that a carload of four men parked behind the Postino Restaurant in Lafayette and the men got out of the car and "disappeared."  At 11 a.m. four men, all dressed in dark clothing and at least one armed with a gun, gathered outside Novina Fine Jewelry at 3559 Mt. Diablo Blvd., brandished the weapon but fled the area when the owner hit an alarm.

Bystanders reported seeing the men jump back into the car as police were called, and it was quickly spotted by a patrolling Lafayette police car on westbound Highway 24.

Lafayette police, backed by California Highway Patrol officers, followed the car at speeds of 60 mph plus and eventually made a traffic stop at 18th and Brush St. in Oakland. Officers immediately detained three men and held them at gunpoint while a fourth managed to get away on foot.

In all four cases Friday, the suspect or suspects were seen fleeing in a gray or dark-colored Toyota, either a Camry or Scion with paper license plates indicating the car had been purchased from a dealer in Berkeley.

The Contra Costa Times reported  police are investigating a possible connection with Saturday's attempted robbery in Lafayette and Friday afternoon's spree.

The first victim in Friday's robberies was walking on North Main Street at Parkside Drive at about 2:50 p.m. when the gunman confronted him. Walnut Creek police Lt. Tim Barrett said the gunman, a black male about 5 feet 9 inches tall with a thin build and a mustache and wearing a black hoodie, displayed a handgun and demanded the victim's belongings. 

The robber fled by jumping into a car and taking off.

Forty minutes later, at 3:30 p.m., another robbery took place in the heart of downtown at South California Boulevard and Bonanza Street. The robber had the same physical description as the robber in the earlier holdup. He also showed a handgun to a pedestrian and demanded the victim's property.

This robber also was seeing fleeing in a dark-colored Toyota, which was driven by a second man.

Just 20 minutes later, at 3:50 p.m., a woman was robbed of cash and other belongings in unincorporated southern Walnut Creek, said Contra Costa sheriff's spokesman Jimmy Lee. The suspect descriptions were the same.

Lee said the two fled in a car that was similar to the one described in the Walnut Creek robberies. 

A fourth robbery occurred just after 4:40 p.m. Friday at the Oakwood Athletic Club  in the 4000 block of Mt. Diablo Boulevard in Lafayette, Lee said. Two black men confronted a woman and demanded she hand over her purse. They kicked her to the ground, then took her purse.