Heavy traffic in Kelley Square, Worcester’s most notorious intersection and the top crash location in the state, stopped two suspects in a Lexus from evading Worcester police on Tuesday, officials said.

A Worcester police officer was on patrol near Harding Street around 1:45 p.m. and saw a white Lexus swerving between the vehicle lane and bicycle lane as the driver kept looking back at the cruiser, police wrote in a statement.

The officer believed the Lexus may have been involved in a crash on Monday and tried to pull the driver over on Madison Street for a lane violation, the statement said. The driver did not stop and drive to get away.

That attempt to flee police was thwarted by heavy traffic in Kelley Square and the Lexus became boxed into traffic, police said.

Officers approached the Lexus. The passenger, identified as Nicholas Perez, 29, of 180 Dewey St., refused to show his hands and was ducking under the seat, the statement said.

Perez was removed from the vehicle and officers found an illegal stun gun, a small amount of what appeared to be heroin and several packages of marijuana, police said.

The driver was identified as Jessalyn Santiago, 19, of Shrewsbury.

Santiago is being charged with failure to stop for police and heroin possession.

Perez is being charged with carrying a firearm without a license, heroin possession with intent to distribute and marijuana possession with intent to distribute.

Both will be arraigned in Worcester District Court.