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HAZELWOOD, MO (KTVI) - A 37-year-old mother is dead and three other people are in serious condition after a gunman opened fire on their car as they were eastbound on Interstate 270 early Sunday morning. The shooting happened near North Lindbergh and left the highway closed for several hours.

The Major Case Squad was activated by Hazelwood Police, Sunday, to begin looking into the incident, which may have ties to a Sauget carjacking and a night spot in Hazelwood within sight of the interchange where the victims appear to have entered the highway.

“We have found evidence on the highway. We have found some spent gunshot shells on the highway,” Hazelwood Police Major Ken Jewson said, regarding the need to divert traffic off 270.

Police say the victims had been at Jay’s Classic Bar and Grill prior to the shooting. Jay’s is located on North Lindbergh, just yards from where the gunfire erupted. The victims, two men and two women, had apparently just entered 270 traveling eastbound, when a second car, believed to be a black Mercedes, pulled alongside and opened fire.

“There were several shots fired at the vehicle, and all four were hit,” Jewson said. “All suffered gunshot wounds and were taken to an area hospital by the driver, who drove straight to the hospital.”

It was there the 37 year old woman, who has at least one teenaged son, died from her wounds.

Detectives are working at least one potential lead in the case. Sauget Police confirm there was a carjacking outside the Route 3 Liquor Store there about 10:30 Saturday night, nearly four hours prior to the attack. The stolen car, a four door black Mercedes, matches the description of the vehicle involved in the Hazelwood shooting. That car was found abandoned about 3:30am, an hour after the four victims were shot.

Sauget police confirm Major Case Squad investigators were on the way both to the scene of the carjacking and the location in St. Louis where the stolen vehicle was recovered to search for clues.

Police have not yet identified the four victims, saying only that two, including the woman killed, were in their thirties, while the other two were in their twenties.

Police say they don’t yet know if the victims knew the assailant, or if any sort of altercation had broken out at Jay’s that might have led to the gunfire.

“We have twenty investigators working on this,” Jewson said. “We’ve activated the Major Case Squad and all that information will come forward.”

County crime scene unit now on 270.Hazelwood PD says EB 270 likely closed for next 2 hours+ at N.Lindbergh.@FOX2now pic.twitter.com/yiigHwUKeZ — George Sells (@GeorgeSells) February 21, 2016

270 east closed at N. Lindbergh. Major Case Squad investigating shooting with 1 dead, 3 more hurt. Details @FOX2now pic.twitter.com/MOXG9mcs62 — George Sells (@GeorgeSells) February 21, 2016

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