BIRMINGHAM, Alabama - More details emerged today following a bizarre Friday night shooting on a Birmingham interstate that involved Mayor William Bell and his security detail.

Sources close to the investigation provided this account of what led to the gunfire that left a man and a woman wounded, a third person in police custody, a badly shaken mayor and the shutdown of busy I-59/20 for hours.

Bell was on his way home from a YMCA fundraiser at the Wine Loft downtown. He was being driven by his security detail, which consists of two sworn Birmingham police officers, a long-standing city practice.

The mayor's vehicle, a Chevrolet Suburban, stopped at a traffic light in the 300 block of Eighth Avenue North, an area known as Little Five Points, as the entourage headed toward the mayor's College Hills home. Bell and the officers then noticed a Lincoln Town Car across the intersection from their car, facing the mayor's vehicle. It was just before 8 p.m.

A man was sitting on the sill of the opened passenger's window, brandishing a handgun. That man then opened fire, flashes of light coming from the muzzle of his gun. He was dressed in dark clothing, and wearing gloves and a skull cap. Two or three shots were fired in the direction of the mayor's car. It's not clear whether the gunman was shooting at the mayor's vehicle, or a nearby Tahoe.

The mayor's security officers continued down Eighth Avenue North, calling in a report of shots fired in the area to the city's police dispatchers and giving them a description of the suspect vehicle. As the mayor's vehicle continued on, the Town Car looped back around and was now back in front of the mayor's vehicle once again, near Ninth Avenue and Arkadelphia.

Gunfire erupted again, in the direction of the mayor's vehicle. The mayor's security officers continued to follow the vehicle, which made its way up onto the interstate. They following at a distance while in communication with marked patrol units and dispatch.

At some point, the security detail officers turned on their emergency blue lights and sirens and continued to follow the Town Car on I-59/20 as it drove increasingly erratically down the roadway.

The Town Car then crashed into the interstate's concrete guardrail near the 22nd Street exit. The officers told the mayor to duck, take cover and stay in the car, which he did. The security detail officers got out of the car and repeatedly told the suspects to get out of the car and show their hands, but to no avail.

The suspects then opened fire again, and the mayor's security officers returned fire and wounded two of the three suspects. North Precinct officers arrived close behind, and took control of the scene. Below the bridge, officers stood guard over a handgun and a small bag of white powder, possibly drugs, that fell or was thrown from the bridge.

Birmingham police have not released the names of any of the suspects or the specific conditions of those wounded. One is life-threatening, the other isn't. Police officials said the Alabama Bureau of Investigation is handling the probe and referred all additional questions to that agency.

ABI has not released any additional information this morning. ABI investigators have asked those involved not to comment pending the ongoing probe.