EAST ST. LOUIS — Three friends went for a casual ride on a Saturday night. Two brought young children with them. They stopped to buy gasoline.

"My sister said they were going riding around and be right back," Dereck Brown said Sunday. "Then we get the call that she'd been shot."

His sister, Raykel N. Gathing, 26, was one of three women, all from East St. Louis, who were fatally shot about 9:30 p.m. Saturday while sitting in a car at a fuel pump. The other victims were Jaimaca McDaniel, 24, and Tanikia Harvey, 26. Gathing and McDaniel had three children, ages 1 to 8, with them in the car but the children were not hit by gunfire.

By Sunday night, Illinois State Police said they had arrested a male suspect, whom they did not identify pending formal charges, at an undisclosed location in St. Louis.

Police said a man approached Harvey's Dodge Caliber while it was parked at a fuel pump at the Crown Food Mart, at Martin Luther King Drive and Collinsville Avenue. He fatally shot all three women, then fled in a white 1993 Mercury Grand Marquis with Illinois plates X101862. Police said they were still looking for the car.

Paramedics rushed the women six blocks to Kenneth Hall Regional Medical Center, where they were pronounced dead.

Police declined to discuss a motive, but relatives of Gathing and McDaniel said before the arrest they believed the shooter to be an ex-boyfriend of McDaniel's. Emma McDaniel, mother of Jaimaca McDaniel, said her daughter broke off the relationship but the man continued to call, and her daughter refused to take him back.

"He told people that if he couldn't have her, nobody could," Emma McDaniel said.

Relatives said the women had been good friends since they were children.

On Sunday, the busy 24-hour store was open for business except at pump number six, where the women were shot — and where friends had placed a big fluffy white teddy bear and long-stem roses.

Jay Makhluf, a co-owner of the store, said he was inside preparing to leave for the night when he heard at least three shots, then went outside to see a crowd gathering around the car. He said the three women had been inside the store a few minutes before.

Dereck Brown said his family will raise his sister's one-year-old son, who was in the car.

"My sister was a beautiful person who loved kids," Brown said. "She had nothing to do with any of this. "