BANGOR – Former agent Frank Spencer’s path to the FBI began when the then-business student watched G-men gun down notorious gangster Al Brady and his crew on Central Street on an October morning in 1937.

Two weeks ago – some 24 years after his retirement from the bureau – that path ended in Birmingham, Ala.

It was there that the 82-year-old Spencer, born in Vinalhaven and raised in Brewer, testified in the historic trial of a former Ku Klux Klansman accused in the 1963 bombing of the Sixteenth Street Baptist Church that killed four black girls.

Spencer on Monday said he and his daughter made the nine-hour trip from his home in Tampa, Fla., so he could help bring to resolution one of the deadliest acts in the civil rights era.

“I had been sleeping with that for 371/2 years,” Spencer said of the relief he felt after a jury deliberated for less than three hours before convicting 62-year-old Thomas Blanton Jr. of murdering the four girls. “It was very satisfying.”

But Spencer’s April 26 testimony, which focused on Blanton’s conflicting accounts of his Klan membership and whereabouts before the bombing, almost didn’t happen.

Just outside Montgomery, Ala., Spencer told his daughter to pull over the car. Short of breath, Spencer, who has a history of heart problems, was taken by ambulance to a local hospital, where he was treated for congestive heart failure.

Under a doctor’s supervision and determined to tell the jury what he had uncovered during his interviews with Blanton, Spencer resolved to help close the most memorable investigation in his 27-year tenure with the bureau.

While Spencer’s career officially began in 1950, he said it was 13 years earlier when he first considered joining FBI Director J. Edgar Hoover’s elite law enforcement team.

While sitting in class at Bangor’s Gilman Commercial School above what is now the Grasshopper Shop, Spencer – fresh out of John Bapst High School – heard the shots.

“I looked out the window and there was the Brady gang,” said Spencer, recalling in detail the FBI’s high-profile shootout with the infamous Indiana gangster wanted in connection with several murders and bank robberies. “I even picked up some of the spent bullets.”

While the excitement of the Brady shootout near his hometown may have steered Spencer toward a career as a federal agent, investigating the racially motivated bombing in one of the South’s most divided cities marked one of his biggest challenges.

“You didn’t know who you were talking to,” Spencer said of his attempts to find those responsible for the deadly blast. “You had a segregationist governor, a police chief turning hoses on black people, and a police force full of Klan members.”

The Rev. John Cross, who led the Sixteenth Street church at the time of the bombing, was grateful for the verdict and met with Spencer and his family after his testimony. Cross said he was duly impressed with the agent’s determination to take the stand.

“He did wonderfully,” Cross, 76, said in a telephone interview Monday from his home in Decatur, Ga. “From the testimony I heard during the trial, there was no way a jury could have come back and said [Blanton] didn’t do it.”

Before last week’s verdict, Blanton had walked free for nearly 38 years since the blast. It had been 24 years since state prosecutors concluded they had insufficient evidence to convict the ex-Klansman.

With the recent surfacing of secretly recorded audiotapes of Blanton discussing the bombing, however, prosecutors reopened the case.

Now sentenced to four life terms, Blanton is the second suspect to be convicted of the Sept. 15, 1963, bombing that killed Denise McNair, 11, and Addie Mae Collins, Carole Robinson and Cynthia Wesley, all 14, as they prepared for Sunday services.

Blanton’s conviction comes more than 20 years after that of Robert Chambliss, thought to be the ringleader in the bombing. Chambliss, convicted in 1977, died in prison in 1985.

Spencer said he was glad to put the lingering case behind him and was hopeful the verdict could bring some sense of closure to the victims’ families.

“Those four little girls were all blown to pieces,” Spencer said at the end of the Monday interview. “That’s what hatred does.”

The Associated Press contributed to this report.