WEST PALM BEACH, Fla. >> On a May morning in 1990, Marlene Warren answered her front door in an upscale Florida suburb to find a clown in an orange wig, red nose and white face paint handing her carnations and foil balloons.

“How pretty!” she exclaimed.

The clown then pulled a gun, shot Warren in the face and drove away. She died two days later.

Now, almost three decades later, authorities say they have arrested the clown: a woman who was said to be having an affair with Warren’s husband and, years after the killing, married him.

Detectives said advances in DNA technology, combined with evidence gathered decades ago, show Sheila Keen Warren, now 54, was the killer.

At the time of the shooting, she was an employee of Marlene Warren’s husband, Michael, at his used car lot. Since 2002, she has been his wife.

She was arrested Tuesday at the home she shared with him in Abingdon, Virginia, and was jailed without bail to await transfer to Florida on first-degree murder charges.

Michael Warren, 65, has not been charged, but detectives refused to rule him out as a suspect and said he was interviewed again Wednesday.

Palm Beach County authorities said Thursday the new examination of DNA collected in 1990 gave them what they needed to arrest Sheila Warren, who had been the primary suspect all along. Without it, there might not have been enough evidence to convince a jury, they said.

“You basically get one shot and if you roll the dice and take that chance and she is found not guilty, you never get that chance again,” said sheriff’s Detective Paige McCann. “Sometimes patience is the best.”

She and Sheriff Ric Bradshaw would not give any details on the genetic material or where it was found.

Sheila Warren’s Virginia attorney, Wayne Austin, said: “She looks forward to having her day in court.” Her husband did not return a call to his home.

Witnesses had told investigators in 1990 that Sheila Warren and Michael Warren were having an affair, though both denied it.

Over the years, detectives say, costume shop employees identified Sheila Warren as the woman who had bought a clown costume a few days earlier.

And one of the two balloons — a silver one that read, “You’re the Greatest” — was sold at only one store, a Publix supermarket near her home. Employees told detectives a woman who looked like Warren had bought the balloons an hour before the shooting.

The presumed getaway car was found abandoned with orange, hair-like fibers inside. The white Chrysler convertible had been reported stolen from Michael Warren’s car lot a month before the shooting. Sheila Warren and her then-husband repossessed cars for him.

Relatives told The Palm Beach Post in 2000 that Marlene Warren, who was 40 when she died, suspected her husband was having an affair and wanted to leave him. But the car lot and other properties were in her name, and she feared what might happen if she did.

She allegedly told her mother, “If anything happens to me, Mike done it.”

Her son, Joe Aherns, who was 21 when he witnessed the killing, celebrated the arrest on his Facebook page and told a friend, “I am happy but sad. … I miss (her) bad.”

Michael Warren was convicted in 1994 of grand theft, racketeering and odometer tampering and served almost four years in prison. He and his wife recently sold a popular restaurant in Kingsport, Tennessee, according to the Bristol Herald Courier.

Neighbor Rocky Blevins told the newspaper Sheila Warren is “a great person,” and his wife, Brook, said: “It has to be a mistake.”