BOSTON (AP) — Suffolk County District Attorney Daniel Conley, who handled high-profile cases including those involving Baby Doe and former New England Patriots tight end Aaron Hernandez, said on Tuesday he won't be seeking another four-year term in November.

Boston's longtime prosecutor said in a public statement and an email to staff that it's time to clear a path for someone else to take the lead running the office.

"I love the job, the office, its staff, and the people and communities we serve," Conley said in the statement. "But I have long believed that those of us fortunate enough to lead as elected officials must also be willing to give others the same opportunity."

Conley's office handled several notorious cases including that of a 2-year-old girl whose remains washed ashore in a trash bag in 2015 and who became known as Baby Doe.

A composite image of the girl was shared by millions of people on social media. An ex-boyfriend of the girl's mother was convicted of murder and was sentenced to life for the killing of the girl, later identified as Bella Bond after a nationwide appeal for information. The girl's mother pleaded guilty to being an accessory after the fact for helping to dispose of her body.

Conley's office also handled a 2017 double-murder trial against Hernandez.

Prosecutors contended Hernandez was responsible for the 2012 shooting deaths of Daniel de Abreu and Safiro Furtado in Boston after one of the men accidentally spilled a drink on Hernandez in a nightclub. The jury in that case found Hernandez not guilty of murder but convicted him of unlawful possession of a gun.

Days later, Hernandez, who was serving a life sentence for his conviction in the 2013 shooting death of a man who was dating his fiancee's sister, killed himself in prison.

Conley, a Democrat, was appointed to the office in 2002 and held the job for 16 years.

He pointed to what he said were some of the changes he helped usher in during his time as prosecutor, including updating the way the office handles eyewitness evidence to help prevent erroneous convictions to treating prostituted youths as victims, not offenders, and bringing more clarity about how the office investigates shootings involving police officers.

"Today our office is fairer, more progressive and more transparent that at any time in its history," Conley said in the staff email.

The Suffolk County district attorney's office is the largest and perhaps most high profile of the state's 11 district attorney's offices. It covers Boston, Chelsea, Revere and Winthrop.