Michelle Frei promoted to trials chief in Chester County District Attorney’s Office.

WEST CHESTER >> Ask Michelle Frei who her favorite teacher was, and she replies immediately.

“My history teacher at Pennsbury High School, Mr. Devlin,” she answers without hesitation. “He was awesome. He didn’t just stand there and lecture. He talked to you. But he made you work. Class participation was a must. There was a lot of discussion, And he made you think. He challenged you intellectually.”

And although Frei has moved on from teacher Ed Devlin’s classroom at the Bucks County high school she graduated from, the idea of teaching as an engagement of ideas, and not simple rote recitation of dry facts, has not been left behind in the dust of her memories.

Frei, in her role as a Chester County prosecutor, continues to pass on, both formally and informally, instruction on the knowledge of the legal — and real — world she has come to know since joining the District Attorney’s Office in 2000.

Now, her role in the office as an unofficial mentor will become more formalized, as she takes over the position as chief deputy district attorney for trials, a position held for the past six years by prosecutor Ronald Yen. The promotion was announced last week by District Attorney Tom Hogan.

“She is a fierce advocate for victims and a formidable adversary for criminals,” Hogan said in a press release marking the move. “She never quits on a case, no matter how difficult the circumstances. She has the respect of her colleagues and the judges.”

Yen requested to move to part-time status, continuing to prosecute individual cases but divesting himself of the administrative duties of chief deputy.

In her new role, Frei will assume responsibility for supervising all of the trial courtrooms, assigning cases to individuals prosecutors and courtroom while also assisting assistant district attorneys with the presentations to judges and juries. Like Yen, however, she will also prosecute selected cases.

“As a career prosecutor, I am excited, grateful, and honored for the opportunity,” she said last week in the press release. “I will strive to continue the commitment to high ethical standards, seeking justice for all of our victims, and fair treatment for criminal defendants maintained by my predecessors. It is a privilege to work for the citizens of Chester County.”

Frei, 47, said her primary advice to those colleagues she serves with is simple. “Rule number one is that you need to be prepared,” she said in an interview at the county Justice Center. You need to be honest with the court. We all make mistakes, but you have to own it.”

Frei has drawn praise from those she tutored in and out of the courtroom.

“Thankfully, as a young prosecutor, I was guided by Michelle,” said Andrew Davis, a former assistant district attorney now in private practice. “Whether discussing case resolution options, honing opening and closing statements, or generally imparting advice and legal knowledge, Michelle spent hours mentoring me as a young prosecutor, as she has many others, which laid the foundation for our legal careers.”

That process of mentoring is less formal, though equally as rewarding, as the other side of Frei’s professional work — teaching fledgling officers at the Montgomery County Municipal Police Academy and the Temple University Law Enforcement Academy. She began work as an instructor in 2005, and has led classes in subjects as wide ranging as Constitutional Law and Rules of Criminal Procedure.

“It is so rewarding to see those kids that you had in class becoming working partners in law enforcement,” she said, naming graduates who now work in municipal police departments in the county or for the Chester County Sheriff’s Office. “I believe there is a process in any profession when you move from being a student, to being a practitioner, to being a mentor, and ultimately being an instructor.”

One of the more important classes that Frei has taught for many years is Domestic Violence Investigation, in which she leads police recruits through the often messy world of violent attacks in the home — boyfriend on girlfriend, girlfriend on boyfriend, husband on wife, parent on child.

Frei’s involvement with such cases came in her first assignment in the county, as one of two prosecutors from the DA’s Office to a Domestic Violence Unit. In it, she worked with multiple police departments and judges in beginning the first true modern approach to such cases. She has continued to work domestic violence prosecutions, as well as to advocate for changes in the law that would benefit ts victims.

She counted among her own mentors during those years now-retired Common Pleas Judge Howard F. Riley Jr., she said. “He was always fair and compassionate with victims. He listened to them. He was an active listener, which is something I think you really need to be. I learned so much from him.”

Frei has continued to work domestic violence prosecutions even after the DA’s unit disbanded, as well as to advocate for changes in the law that would benefit its victims.

She played a vital role in working with the Domestic Violence Center of Chester County to create the Lethality Assessment Program, a tool that uses a series of simple questions to victims to help the police predict which domestic violence cases are likely to lead to extreme violence. This program allows the police to intervene early, getting help for the victim before the case turns into a homicide, according to the DA’s press release.

Dolly Wideman-Scott, the head of the Domestic Violence Center of Chester County, paid tribute to her “genuine concern for the safety of victims and an unerring sense of justice.”

Her work has drawn her into several high profile cases in the county’s recent history, including the murder of Kimberly Hvizda, the estranged wife of a former minor league baseball player who stabbed her in the parking lot of an Upper Uwchlan Wawa where she worked; the shotgun slaying of Jamica Woods, a longtime victim who had made the decision to leave her abusive boyfriend and start a new life before he killed her; and the brutal torture and death of 3-year-old Scotty McMillan, a case that made international headlines.

All three of the defendants in those cases were sentenced to life in prison, sentences won by Frei without trial.

“Over the years, this job will break your heart, time and time again,” she told an interviewer who asked why she devoted herself to those cases “You see so many innocent victims. But I guess it is my warrior motivation. You fight for the innocent. I thought about doing other things professionally. But I cannot imagine doing anything different. This is what I want to do.”

Frei received her undergraduate degree from Gettysburg College. She received her law degree from Villanova University School of Law. A former soccer player until a foot injury sidelined her, Frei enjoys mountain climbing and all of the physical fitness training that is required for the sport.