JACKSONVILLE, Fla. – A man accused of shooting his ex-fiancee in the head as she was leaving her Southbank workplace late Thursday afternoon was a former undercover detective from Connecticut who moved to Florida after receiving threats, News4Jax has learned.

The Jacksonville Sheriff's Office identified the woman as Lynn Herriott, 47, and the gunman as William Chase Jr., 58.

Chase was in the hospital in critical condition after trying to take his own life following the shooting and died from his injuries Monday night, the Jacksonville Sheriff's Office said.

Chase worked as an undercover officer for the Bridgeport (Connecticut) Police Department and began going by the name Dexter Levin after he moved to Florida. He published a book in 1994 about his undercover life, called “Chased: Alone, Black and Undercover.”

VIDEO: Chase wrote book on being undercover cop

Published reports in Connecticut from police chief A.J. Perez said, “The threats on his life were very real. Pray for him and his family and remain hopeful. He lost who he was and his identity and even he could not explain it.”

Chase's book details his life as a black undercover officer and what it did to his mental state.

The following is an excerpt from the book:

Sometimes I felt like I was a government experiment, a test tube in a lab, a secret weapon never before launched. We needed training programs for undercovers, we need to provide them with stress management so that they can deal with the manipulations, the threats, the everyday dangers of the job.

According to police, Herriott was shot just after 5 p.m. Thursday in a parking lot off Riverplace Boulevard.

Police said Chase was waiting for her to get off work and shot her six to seven times before turning the gun on himself. Both suffered life-threatening injuries and were taken to UF Health Jacksonville.

"Right now, she's really fighting for her life in critical condition," Natasha Bridges, Herriott's sister, told News4Jax. "I just feel like the police system, the law needs to do a better job when it comes to domestic violence because now she's fighting for her life."

Bridges said her sister had brain surgery and lost an eye. She said Herriott is a mother of three children who worked in the foster care office contracted by the Florida Department of Children and Families.

Accused shooter has violent history

In the two decades he had lived in Florida, Chase was married and divorced twice in Jacksonville.

Herriott and Chase had a rocky relationship leading up to the shooting, according to documents.

Herriott had a restraining order against Chase after a breakup earlier this year. Another woman tried to get a restraining order against him in 2011, but that was denied.

Clay County court records show Herriott had sought restraining orders against her onetime fiancé, Dexter Levin, three times over incidents of domestic violence. Jacksonville police said Chase carried identification as Levin.

Chase was arrested, under the name Levin, by Clay County deputies after he pushed his way into Herriott's home on Feb. 19. He was charged with kidnapping, aggravated domestic assault, aggravated domestic battery and armed burglary. That report indicates the couple was together for five years, but after the relationship ended in December, he repeatedly tried to contact her.

According to the arrest report, Chase held a gun to her head and tried to strangle her. Herriott said Chase told her he was going to kill her and kill himself. She told deputies he eventually released her and she ran, screaming to a neighbor's house to get help.

Herriott told Clay County investigators she changed her phone number and discontinued her email account, saying that he had been sending her an average of 20 emails every day. He told deputies that he stopped trying to contact her after she gave back the engagement ring on Feb. 9.

Chase was out on bond with a court order mandating no contact with Herriott. He was due back in court on June 22.

A friend who knew Chase from his undercover days told News4Jax on Monday that he had tried to get Chase help and spoke to him last week about his problems.

“We were talking extensively about this issue that he and Lynn were going through and I kept reminding him, 'Let it go. Let it go. Let her go,' and he seemed to be doing that,” Mark Kerrin said. “There was no indication whatsoever that he was going to snap. I knew something was wrong.”

Kerrin, who teaches forensics at several local colleges, said he stressed to his friend that he needed to get everything out in the open.

“We are always looking over our shoulder from that world we come from,” Kerrin said. “Laypeople call it undercover. Some people call it the cover. But it's layers of intelligence operations.”

Bridges said her family was not fully aware of Chase's undercover background.

Detectives were interviewing witnesses and trying to obtain surveillance footage from area businesses, but haven't said much else about the case.