A former Suffolk County Sheriff's Department employee will launch a bid for the sheriff's seat, challenging nine-year incumbent Steve Tompkins.

Sandy Zamor Calixte, a 16-year veteran of the department, will formally announce her candidacy Wednesday in Mattapan.

"For the last two decades, I have done the work behind the scenes to make our Department more equitable, transparent, and community-centered," said Calixte in a statement about her bid. "But after working within the system pushing behind the scenes for change, it is clear to me that the only way to implement the change we need in this Department to better serve our community is new leadership."

"I have tremendous respect for the current Sheriff, but this run is not about any one person, " she continued. "it’s about changing a system to give people the services they need to have a second chance."

The incumbent Tompkins confirmed he will seek re-election.

"I fully intend to run to retain my seat," Tompkins told GBH News. "We've done some incredible work from 2002 on," he said, pointing to his time within the department before running for the sheriff's seat.

Tompkins started at the Suffolk County Sheriff's department in 2002 as director of communications and was promoted in 2005 to chief of external affairs, the same role Calixte held up until Tuesday, when she resigned.

Later, in 2013, Tompkins was tapped by then-Governor Deval Patrick to serve as interim sheriff in 2013. He ran to serve out the remainder of his predecessor's term outright a year later.

Since then Tompkins has faced one primary challenger, Alexander Rhalimi, who he defeated handily in his 2016 campaign.

“Sandy has been a valued member of the Suffolk County Sheriff’s Department since 2006,” Tompkins said of his new challenger. “I hate to lose her, but I welcome her to the battlefield. Let’s dance.”

Asked what she might do differently if elected, Calixte said she is running to make the department a place "where people leave better than when they came" and where "our staff comes to work every day proud" to be a part of systemic change.

Calixte first joined the Sheriff's Department in 2006 as the coordinator of community outreach and youth programming. She was promoted to director of external affairs in 2013, then chief of external affairs a year later.

She holds a Masters Degree in Criminal Justice and a Bachelor of Arts in Psychology from Northeastern University as well as a Graduate Certificate in Social Justice from Harvard Extension School.