Kris Arneson, assistant police chief in Minneapolis, who earned a reputation as a fierce advocate for women in law enforcement as she rose to become the department's second in command, will retire in April.

Her last day will be April 30, according to an e-mail from Chief JaneƩ Harteau to Mayor Betsy Hodges and the City Council, which gave no reason for her departure.

Her replacement hasn't been named, the e-mail said.

"I'm sure many of you may be wondering who will replace Assistant Chief Arneson. That is something we will be working on in the coming weeks," Harteau said in the e-mail. "We want to be thoughtful and thorough as we fill this important position, and we're asking for your patience as we work through this process." She added that the vacancy may not be filled until the fall.

Harteau also said that Arneson "leaves a strong legacy. She is a passionate and dedicated leader. ... Although I am happy for her to begin this next chapter, her loss will be felt, and she will be difficult to replace."

Arneson joined the department in 1986 after a short stint with Savage police, and moved up the ranks, becoming assistant chief in 2015.

At the time, Harteau called her appointment "an easy choice."

Before becoming assistant chief, Arneson served for three years as deputy chief.

Throughout her career, she has gained recognition for her efforts to advance women in policing.

She oversaw the 2010 International Association of Women Police training conference and received the "Officer of the Year" award from the Minnesota Association of Women Police earlier in her career, according to an online biography.

She holds a bachelor's degree in criminal justice from Metropolitan State University and a master's in police leadership and education from the University of St. Thomas.