When Sheila Keen-Warren realized Tuesday that she was being arrested for the 1990 murder of a Wellington woman, she sighed and buried her face in her hands.

After 27 years of escaping justice, Keen-Warren was taken into custody not far from her home in Abingdon, Va., near the Tennessee border. Authorities say she dressed as a clown on May 26, 1990, and presented Marlene Warren with flowers and balloons labeled "You’re the Greatest!" before shooting her in the face. Marlene Warren, who was 40, died two days later.

"Even for her it was, ‘Look, it’s over,’ " Capt. Michael Wallace, who supervises the Palm Beach County Sheriff’s Office Cold Case Unit, said of Keen-Warren’s demeanor following her arrest. "She’d been running for 27 years. She probably thought she had gotten away with it. But she didn’t."

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Keen-Warren, 54, remained Thursday at the Southwest Virginia Regional Jail in Abingdon awaiting extradition to Palm Beach County. That is expected to come within the next several days. She faces a charge of first-degree murder with a firearm.

Prosecutors will wait until Keen-Warren returns from Virginia to decide whether they will seek the death penalty, State Attorney Dave Aronberg said Thursday. She is eligible for a death-penalty charge.

PBSO Detective Paige McCann said the investigation continues into whether to charge Keen-Warren’s husband, Michael. He was married to Marlene Warren at the time of her fatal shooting, but authorities were told that Michael Warren and Keen-Warren having an affair. They married in 2002.

Detectives interviewed Michael Warren, now 65, on Wednesday, McCann said. He was sentenced in Palm Beach County to five years in prison after his conviction in 1994 of grand theft, racketeering and odometer tampering.

"We don’t know if anybody else will be charged in this," PBSO Sheriff Ric Bradshaw said at Thursday’s news conference. "That remains to be seen."

Detectives investigated Marlene Warren’s murder for years before it went "inactive" for nearly a decade, Wallace said. The investigation resumed in 2014, and renewed analysis of DNA evidence led to Keen-Warren’s arrest.

"We knew she did it in 1990," Wallace said. "But if we had arrested her back then, maybe we get a conviction and maybe we don’t. If we don’t, then she would have been done with this."

McCann gave a description Thursday of the murder, re-telling how Keen-Warren got out of a stolen Chrysler LeBaron dressed as a clown wearing an orange wig and a red nose. She walked up to Marlene Warren’s front door in the Wellington Aero Club community on the west side of the village. Marlene Warren accepted the flowers and balloons then responded, ‘How nice," before she was shot point-blank in the face. Inside the home were Marlene Warren’s 21-year-old son and his friends.

"Witnesses at the scene said the clown just turned around, walked back to the car … and drove away, very calmly," McCann said.

Keen-Warren was immediately identified as a prime suspect. But McCann said prosecutors didn’t sign off on charging Keen-Warren until old evidence submitted for new DNA analysis tied her to the killing and resulted in a grand jury issuing a murder indictment.

"You get one shot," McCann said of charging Keen-Warren. "Sometimes, patience is best."

Detectives declined Thursday to reveal what specifically helped them break the case and provided few details of the evidence against Keen-Warren. McCann did say that the murder weapon has never been found.

Keen-Warren waived her right to fight an extradition request to Florida during a brief court hearing on Wednesday.

Wallace, whose detectives broke the case, speculated that Keen-Warren may have felt "relief that she didn’t have to run from this anymore."

Wallace’s Cold Case Unit has solved seven decades-long cases in 2017. That includes the murder of Jean Savage, a Delray Beach housewife who was beaten, raped and stabbed to death on June 4, 1975. DNA matched James Franklin Rose, an inmate on death row for killing an 8-year-old girl, to Savage’s murder.

"Cold cases are very difficult to solve," Bradshaw said. "It’s one thing to think somebody did something. It’s another thing to know they did it and be able to prove it in court."

While Aronberg has not announced if his office will seek the death penalty if Keen-Warren is convicted, recent history shows that death sentences are extremely rare in Palm Beach County. It’s been at least two decades since a jury imposed a death sentence in state court in Palm Beach County.

Since 2010, only three Palm Beach County juries have had to decide between life and death sentences, and all three came back quickly with life verdicts. In other cases, prosecutors have either abandoned their pursuit of the death penalty or ended the cases with plea agreements.

That list includes a case involving Kimberly Lucas, who was facing the death penalty for drowning the 2-year-old child she shared with her ex-partner. Lucas accepted a plea deal this week of life plus 30 years, avoiding a trial.