9:58 PM: If you have to head south any time soon, you’ll want to avoid southbound Highway 509. It’s blocked a mile or so south of Cloverdale because of a crash involving drivers described as a suspect and victim in a West Seattle incident – the victim was said to be following the suspect after some kind of incident, possibly involving a gun, which officers say may have been thrown out of a car window on the West Seattle Bridge. Lots to sort out but in the meantime, southbound 509 is said to be fully blocked.

10:34 PM: Listening back to archived emergency-radio exchanges, this began with the victim alleging the suspect had shot at him “in a parking lot on Harbor Avenue.” Police are reported to have taken the suspect into custody at the crash scene.

10:59 PM: Police have told dispatch they’re reopening part of the freeway.

ADDED 11:11 AM MONDAY: Here’s the initial SPD summary, which says the first word of this came in a 911 call at 9:30 pm:

… a man called police after having exited his parking garage in the 3400 block of Harbor Av Sw, and gotten involved in a road rage incident. According to the victim, he may have mistakenly cut off two occupants of a black BMW, who exited their vehicle, with the passenger punching him in the face multiple times, and the driver brandishing a handgun. The victim said that before he could put his vehicle in drive, he heard his vehicle being struck by gunfire. While on the phone with 911, who told him multiple times to pull over, the victim said he was following the suspect vehicle across the West Seattle bridge in an attempt to get the suspect vehicle license plate. However, minutes later while traveling sbound on SR-509, both vehicles were involved in a collision. Only the driver was seen exiting the suspect vehicle, where he was positively identified at the scene by the victim and taken in to custody. A brief while later, the passenger returned to the scene on foot with his mother, where he was also positively identified and placed under arrest. There were no injuries. Both suspects were arrested for Investigation of Assault. As bullet holes were found in the victim vehicle, it was impounded with an investigative hold alongside the suspect vehicle. SFD, State Patrol, Tukwila and Renton Police assisted in this incident. GVRU, Homicide, TCIS, and even Harbor were contacted about this matter, as the suspect with the firearm claimed he tossed it over the West Seattle bridge. Spent shell casings were recovered at the original scene and placed into evidence.

In case you’re wondering, Tukwila and Renton were contacted because SPD was trying to find a K-9 team to help them look for the gun; they eventually got a response from Tukwila.