Story highlights Police say the shooter dictated his last will and testament immediately before the attack

Michael Ford is in custody, as are his brothers Elijah Ford and Malik Ford

Jacai Colson would have celebrated his 29th birthday this week

(CNN) The Maryland officer who died after a gunman opened fire on a police station Sunday was struck by friendly fire.

An autopsy on Jacai Colson showed he was "inadvertently shot by a fellow responding officer during the gunbattle," police said a day after the attack.

They identified the suspect who shot at the building as 22-year-old Michael Ford. He is in custody and remains hospitalized after being injured during the exchange of gunfire. His brothers, Elijah Ford and Malik Ford, are also in custody.

All three will be charged with second-degree murder, six counts of attempted first-degree murder, nine counts of use of a handgun in the commission of a felony and additional charges, according to police.

3 brothers in custody in ambush of police station, officer killed after gunman opens fire. https://t.co/JXI9Py56vn pic.twitter.com/CvQUPMvAmv — PGPDNEWS (@PGPDNews) March 14, 2016

Police said the shooting was recorded by the Ford brothers.

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