A Florida woman is behind bars after she was accused of killing not just one, but two of her ex-husbands on the same day, the sheriff's office said.

Susan Avalon, a 51-year-old Citrus County woman, was arrested and charged with the second-degree murder of a 54-year-old Bradenton man on Wednesday night, the Manatee County Sheriff's Office (MCSO) told the Bradenton Herald. His name has not been released due to Marsy's Law. According to Manatee County Sheriff Rick Wells, prosecutors plan on seeking a more severe charge.

Meanwhile, the Tampa Police Department is working with the State Attorney's Office to determine what charges to file after investigators learned that Avalon had allegedly killed another ex-husband hours before in Hillsborough County, according to the CBS News affiliate WTSP.

According to multiple reports, Avalon was booked in Citrus County and made her first court appearance on Thursday. MCSO is seeking the death penalty against her, Wells said.

Woman arrested in a "brazen" murder

Investigators believe that Wednesday's Bradenton killing was part of a "brazen" double homicide that began earlier in the same day in Hillsborough County, where Avalon allegedly shot her second ex-husband to death before traveling to Manatee County, Wells said.

He continued, saying that investigators realized the scope of the case when they confronted Avalon at her Citrus County home.

"Detectives let her know they are there to speak about her ex-husband," Wells said. "She says, 'Which one?'"

She disguised herself as a food delivery driver so she could get close to her ex-husband

MCSO said it responded to reports of a shooting on Wednesday afternoon at a home in the 7000 block of Chatum Light Run in Bradenton's Heritage Harbour community around 2:55 p.m. That's where deputies found the man suffering from a gunshot wound, the Bradenton Herald reported.

"It doesn't get any more brazen than this," Wells said. "This is a very active neighborhood -- three o'clock in the afternoon on a Wednesday, kids coming home from school. She didn't seem to care."

According to investigators, the man told deputies that the shooter -- later identified as Avalon -- came to his home and shot him after he answered the door. The Bradenton Herald reported that detectives previously believed the shooting was targeted and not a random act of violence.

Detectives later determined that Avalon had allegedly used stolen food from a nearby Panera and posed as a delivery driver to make contact with the man, WTSP reported.

According to the sheriff's office, the man was taken to the hospital, where he died from his injuries. Wells said deputies were able to talk with him before he died.

"Deputies asked him this, 'Who could have done this to you?' And he says, 'Possibly my ex-wife,'" he said.

MCSO investigators said information provided by the man and evidence collected during the investigation led to Avalon's arrest.

The man's teenage daughter was inside the home when the shooting happened

According to the Bradenton Herald, the man's 15-year-old daughter was inside the home when he was shot. While she did not witness the shooting, she heard the gunfire and reported to MCSO that she saw a silver Honda Odyssey "driven by a masked person wearing a gray sweatshirt" leaving the area, Wells said.

Investigators later learned that Avalon had owned a silver Odyssey and by using license plate reader technology, detectives were able to track the vehicle traveling south across the Sunshine Skyway Bridge and back toward Citrus County, where she lives.

When detectives arrived at Avalon's home, they watched her allegedly try to destroy evidence, Wells said.

"She comes out of her house for bleach and cleaning rags, gets into the silver Odyssey and begins to wipe down the car," he said.

Investigators' questioning led them to believe there was more than one victim

It was during that confrontation that Wells said investigators realized there was more than one victim in the case when Avalon asked them to clarify which ex-husband they were asking her about.

According to Wells, Avalon also made statements to the detectives, claiming that her ex-husband was "a child abuser and a molester," and at one point, confused them for being officials with Hillsborough County Sheriff's Office, WTSP reported.

It was at this moment that MCSO began looking into Avalon's second ex-husband and discovered that he lives in Tampa, Wells said.

Tampa Police were informed and went to the second ex-husband's home, but initially got no answer when they arrived. Officers reported finding damage near the rear door before entering the home and finding the second ex-husband, who was also shot and killed, WTSP reported.

Acted "out of character" when she came home, her boyfriend says

Wells said Avalon has not otherwise cooperated with investigators or provided a statement about the deaths. Instead, his detectives gathered information by questioning her live-in boyfriend.

According to Wells, Avalon's boyfriend said that she made an unusual remark to him earlier that day, saying that she loved him "in case something happens to her, a statement he claimed was out of character for her, the Bradenton Herald reported. WTSP reported that Avalon's boyfriend said she had recently discovered where her ex-husband was staying, but did not specify which man she was referring to.

Wells continued, saying that Avalon's boyfriend described her actions when she returned home, saying she entered the shower fully clothed while still wearing a gray sweatshirt and even made derogatory comments about her ex-husbands, but never confessed to the shootings.

A history of child abuse and custody battles

Wells said that Avalon and the Bradenton man had been divorced for about 10 years and had issues with custody and child support, for which she owed him around $4,000, WTSP reported.

Investigators said they believed that the violent act may be connected to her ongoing personal disputes. According to Wells, Avalon also faced a potential driver's license suspension later this month if the balance wasn't paid, the Bradenton Herald reported.

Wells also said that Avalon had prior arrests related to child abuse and custody disputes dating back to 2004, including a case in Virginia, while other cases in Tampa and Pasco County were later dropped. According to WTSP, Avalon reportedly has five children between her and the two ex-husbands.

Wells said she had no other significant criminal history, the Bradenton Herald reported.