Every day, they pass pictures of the officer and his family as they walk through the station's halls. One image shows his daughter, Holly, wearing his cap and seated at his desk the day his wife came to clean it out for the last time.
Prothero died 13 years ago, shot three times responding to a jewelry store robbery while working a second job as a security guard. He left behind a family with five children under the age of 6, in addition to his grieving colleagues.
But it was one of Prothero's killers who gained wider fame. Wesley Moore became the subject of a best-selling book, "The Other Wes Moore," and his notoriety has grown.
The book has been added to reading lists across the country, including at schools attended by Moore's and Prothero's children. Much of Prothero's family has read it, though his brother said they did not support its being published, fearing it would give undeserved attention to a "cop killer."
Today, police officers are determined that none forget Prothero or his contributions. They continue to collect donations for Prothero's family through a snack sale at the precinct, where officers drop cash into an old coffee can and grab a bag of chips or a candy bar. They send Christmas and birthday cards. They visit a plaque placed in the precinct's memorial garden in his honor.
And they show up in court in force, as Moore continues a fight to have his conviction overturned. It happened again last month, when Moore argued for a new trial.
"We deal with this every day," said Sgt. David Neral, who worked with Prothero at the precinct and remains close with Prothero's family.
While many have moved on to other assignments or retired, Neral and several other officers packed into Baltimore County Circuit Court. They waited anxiously to hear whether Moore, 37, would succeed. Moore's and Prothero's families were there, too.
Moore sat just feet away in jeans, leg shackles and a light blue shirt with "DOC" written on the back. He was asking for a new trial, based on revelations that one of the state's witnesses in his case was related to a juror through marriage. Moore also argued that he was not properly advised of his right to a bench trial.
In the end, Judge Judith C. Ensor denied the request, and Moore's attorney, Flynn M. Owens, said he was contemplating an appeal. Moore has until July 19 to request one.
"We may be coming close to an end," said Prothero's brother, Rick. "You get a little bit used to it now. We get kind of used to being here."
The family has sat through several post-conviction hearings and appeal attempts. Each one forces them to relive the events of Feb. 7, 2000, when Prothero was shot as he chased four robbers fleeing from J. Brown Jewelers on Reisterstown Road.
Prothero was pronounced dead 45 minutes later at the hospital. Moore and his half-brother were arrested 12 days later in Philadelphia after a multistate manhunt.
All four men charged in the shooting were later sentenced to life without the possibility of parole, including Wesley Moore's half-brother, Richard Antonio Moore, who was identified as the shooter, Donald Antonio White Jr., and Troy White.
A salesclerk identified Wesley Moore as one of the gunmen in the store.
The case entered the national consciousness through a popular book by author Wes Moore, who was born in Southern Maryland, raised in New York and became a Rhodes scholar. The book, published in 2011, described the parallels between the men's lives and where their paths diverged.
The author Wes Moore said he was aware that some of Prothero's family did not support the book. He said he never intended to excuse the crime or cause the family pain.
In the book's foreword, the author said he wrote about their lives "as a way of thinking about choices and accountability, not just for each of us as individuals but for all of us as a society."
But, in the opinion of his fellow officers, it is only Prothero's name that is necessary to recall at the precinct.