A longtime New York City prosecutor and former judge who presided over the arraignment of "Son of Sam" killer David Berkowitz will retire at the end of the year, he told NY1 on Wednesday.

Queens District Attorney Richard Brown, who was appointed in 1991, said he plans on completing his term but would not seek re-election. The 86-year-old has been battling Parkinson's disease for the past few years and said he came to the decision "after careful thought and consideration."

"It was not an easy decision. I find it difficult at times to be as mobile as I use to be," he said in a phone interview after the news broke on NY1.

The career of Brown, a Democrat, spans six decades. He became a judge in 1973. Four years later, he presided over the arraignment of the "Son of Sam" killer.

Brown was never a prosecutor until Gov. Mario Cuomo picked him from 14 candidates to replace retiring DA John Santucci in June 1991 and was elected to a full term that November.  Never facing a major opponent, he won re-election six times. But he had become frail in recent years.

"It was my decision that was made with my wife and my children and my two granddaughters," Brown said. "They have reached a point where they want me home."

As Queens district attorney, he was no stranger to the press, with his elaborate news conferences and crime scene visits. The "Wendy's Massacre" of 2000 was a haunting moment in his career. 7 restaurant employees were shot execution style by a former employee and an accomplice. 5 died.

"I will never forget being in that basement refrigerator in the middle of the night," Brown said in 2007.

Brown was considered a tough and successful DA, but in 2008 he faced a rare moment of criticism when three detectives were acquitted in the shooting death of Sean Bell on Bell's wedding day.

In recent years, there was talk Brown had become less and less involved in the day-to-day operation of his office because of poor health, including a heart valve procedure.

It was something he always denied. "I have a constant knowledge of what's going on," he said.

Crime spiked and then plunged under Brown, as it did across the city. He was known to push for alternative sentencing to give young offenders who deserved it a second chance. And in 2017, he joined with three other DAs in dismissing nearly 650,000 old arrest warrants for minor infractions. His "Say No to Violence" initiative had a huge impact on young students in Far Rockaway, Queens.

"We're very proud of the fact that we turned so many lives around," he said.

Brown had hoped he would become the city's longest serving district attorney, but he fell short of the 34 years his friend Robert Morgenthau served as the Manhattan district attorney.

Information from the Associated Press was used in this story.