A 21 year-old black trans woman was shot in the head and left in an alley before being discovered and rushed to hospital where she died later that night.

Police in Montgomery Village, Maryland are treating the murder as a hate crime after a witness came forward saying that they heard four gunshots following an what sounded like an argument between Zella Ziona (21) and a group of teenagers last Thursday.

Police have arrested local man Rico Hector Leblond in connection with the murder.

“They argued and things happened so fast,” the witness told a local broadcaster. “I don’t know what they argued for.”

Police are appealing to more witnesses in the area for any information regarding the incident.

“We are not ruling out the possibility that this could be hate-based,” Montgomery County police spokesman Capt. Paul Starks told NBC Washington.

Friends of the victim paid tribute following the news of her death. “She was amazing,” said Barbie Johnson, “When Zella’s around, there’s not a single frown in the room.”

Another added, “It’s tragic. Senseless violence is something none of us wants to live around.”

Zella is just one of 21 known trans women who were murdered in the US this year, however the number could be even higher. Of those 21, 17 of the victims were women of colour.