One Maryland firefighter is dead and a former colleague is in jail facing charges related to his murder.

According to the Baltmimore Sun, 35-year-old Daniel Greene was arrested on suspicion of first-degree murder in the shooting death of 31-year-old John Hickey late last month.

As WJZ reported, authorities responded to Hickey’s locked apartment after receiving a request for a welfare check at the location.

There was no indication anything had been taken from the residence by the perpetrator.

The Upper Fells Point man was found dead in his home on November 30 with an apparent gunshot wound to his head.

Greene, of Norrisville, was arrested Tuesday in connection to the death, which medical examiners ruled a homicide. He was reportedly employed until 2013 as a Prince George’s County firefighter, a position he held for more than a decade.

Authorities released little information about the investigation or the crime itself, stating only that it was “domestic related.”

Firehouse.com reported that Hickey had been a firefighter with several agencies in the Baltimore area and was supposed to begin training at the Baltimore City fire academy this month.

“He was a volunteer firefighter EMT on his way to becoming a professional firefighter like his grandfather in the BCFD,” Hickey’s family said in a statement. “He loved baseball and the Orioles.”

The family went on to call on “the person that did this” to “please turn yourself in and to anyone that has any information please call the police.”

Hickey’s funeral service is scheduled for Thursday afternoon in Sykesville.

[Featured image: Daniel Green/Baltimore Police Department — Jon Hickey/Lansdowne Volunteer Fire Department]