Kennewick police are still seeking a possible witness to a fatal car-vs-pedestrian accident late Tuesday. Updated information has been released from investigation.

Shortly after 4pm, 52-year-old Nina Howard was trying to cross 27th Ave. in Kennewick, just West of Ely St. when she was struck by a passing motorist.

An Eastbound 1966 Chevy Nova driven by 46-year-old Michael Johnson struck Howard as she was crossing.  Kennewick police say while Howard was crossing mid-block and not using the crosswalk,  the speed of Johnson's vehicle appeared to be a factor in the accident.

Attempts to revive Howard at the scene were unsuccessful and she was pronounced dead at the scene.  The area around 27th and Ely (near Heritage Nursery and the Waste Management Transfer Station) were closed off for several hours during the investigation.

Kennewick police say there may have been a landscaping truck pulling a trailer that was also heading in the same direction at the time of the accident. Police say the driver is considered a witness and they are wanting to speak to them.

Late Tuesday evening,  after meeting with investigators,  Benton County Prosecutor Andy Miller authorized the driver, Johnson, to be booked into the Benton County Jail on a 72-hour hold for Vehicular Homicide.

UPDATE - according to court reports and investigation notes,   Johnson was reportedly racing his 18-year-old son Aaron Johnson shortly before the accident.  Police reports indicate Michael Johnson told police he was driving faster than 50 mph. but the speedometer in his car doesn't work. His son Aaron was driving a 1989 Mustang, and the two reportedly began to "race" each other down 27th . Aaron admitted his attained speeds of 55-60 mph during the race.  The accident occurred shortly after the two had passed a commercial truck, and the Chevy moved into the left lane, with the Ford in the right.  Aaron Johnson also told police he estimated his father's car was going perhaps 60 to 70 mph when he heard him back off the throttle and hit the brakes hard.

The elder Johnson also told reportedly takes lithium a few times a day, and had taken some about two hours before the crash.  He also uses medical marijuana in oil form, and told police he last smoked it Monday night.  One report indicated Johnson was described as very "lethargic" and unemotional after the accident.

If charges are filed,  Johnson will be back in court April 17th, according to court documents.