PORTLAND, Maine — Portland Police announced Friday night that they arrested a man in connection with the murder of 22-year-old Isahak Muse.

Police identified the man as 24-year-old Mark Cardilli Jr. Police took Cardilli into custody at 5:30 p.m. on April 5.

Police said Muse was shot and killed on March 16 at a home at 107 Milton Street in Portland after an altercation. Police said Cardilli lives at that address with his family.

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The arrest comes almost three weeks since Muse's murder inside of 107 Milton Street in Portland. 

A grand jury indicted Cardilli on Friday.

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"Detectives have worked tirelessly over these three weeks to gather the evidence needed to bring the case to the grand jury. There is still more work to be done and we will not be releasing any further information," said Lt. Robert Martin with Portland PD. "We will continue to work with the Muse family during this time and we thank them for their patience and understanding during the past three weeks and while we continue our investigation."

Cardilli was once in the Portland Police "Explorer" program, which invites high school students interested in law enforcement careers to learn what the jobs entail.

Left to right Sgt. Farris (post advisor) Explorer Sgt. Jesse Dibiase, Explorer Lt. Alicia Leourm, Explorer Chief Mark Cardilli and Police Chief Michael Sauschuck.

Muse's older brother runs a Facebook group called "Justice for Isahak," and wrote in a Facebook post following the news: