DENVER — The man accused of gunning down an RTD security officer in downtown Denver was charged with first-degree murder while making his first court appearance on Friday morning, the Denver District Attorney’s Office said.

Joshua Cummings is accused of shooting Scott Von Lanken on Tuesday night near Union Station. The Denver Police Department said the RTD guard might have been killed because of his uniform.

Cummings, whose hands and feet were shackled, was advised he is being charged with first-degree murder in Von Lanken’s death.

Cummings had a scraggly beard, a knot on his forehead and a swollen eye. Denver District Attorney Beth McCann said the swollen eye was from an infection and not related to his arrest.

Cummings asked for a Quran as he was escorted from the courtroom. No bond was set and his next court appearance is March 3.

The Denver Muslim community said Thursday it warned federal agents about Cummings last year.

Cummings was arrested about 20 minutes after the shooting at 16th and Wynkoop streets. A Denver mosque said it sent a letter to federal authorities on Christmas Eve warning them about Cummings.

The letter raised a red flag about Cummings’ behavior and beliefs, and said mosque members believed he was becoming very radicalized and they worried about what he might do.

Von Lanken’s wife said her husband had been a police officer and a pastor, and was proud of the way he served his community.

“He would have died for anybody that night. If he took that place … if another police officer … if he took the place of that man, he would have been honored to have done that,” Shellie Von Lanken said.

A service for Von Lanken will be held Monday.