NEW YORK -- Knicks guard Reggie Bullock took to Instagram on Wednesday afternoon to share a photo mourning the loss of his sister Keiosha Moore.

Moore, who sustained a fatal bullet wound to the chest, was one of nine people shot in Baltimore on Monday, according to a police spokesman. Three of those shot died. Moore was 22.

Bullock's sister Mia Henderson, who was a transgender woman, was stabbed to death in Baltimore in 2014. Henderson was the oldest of Bullock's four siblings and was 3½ years older than him. At the time, Bullock played for the Los Angeles Clippers.

"I never felt so BROKEN in my life," Bullock said Wednesday on Instagram. "I failed as a brother to protect you from the harm of these streets. I FAILED TWICE, to be the TRUE BROTHERS KEEPER!"

According to police records, 283 people have been killed in Baltimore so far this year, up from 258 at the same time last year. Another 663 people have been wounded in shootings in 2019, compared to 553 at this time last year.

Three weeks after Henderson's death in 2014, Shawn Oliver was arrested and charged with first-degree murder. DNA matching Oliver's was found under Henderson's fingernails. When Oliver was acquitted of all counts in 2017, Bullock was in the gallery and tweeted his reaction.

NOT GUILTY. ? #standupforMIA

— Reggie Bullock (@ReggieBullock35) January 12, 2017

On Wednesday, Bullock again took to Twitter, writing, "Let's see if y'all can go atleast 1/2?" in apparent reference to the lack of conviction in Henderson's case. Oliver is currently serving a 10-year sentence on a drug charge unrelated to Henderson's death.

After Henderson's death, Bullock, 28, became an advocate for LGBTQ rights. He works with the Gay and Lesbian Alliance Against Defamation and in 2018 became the first active NBA player to ride on the league's float in the New York City gay pride parade. Bullock has also said he would welcome a transgender man playing in the NBA.

Bullock was away from the team Monday when the Knicks played the Chicago Bulls at Madison Square Garden. Bullock, who underwent surgery on a herniated disk in July, has yet to play this season.

Team president Steve Mills addressed Bullock's loss and the death of a family member of guard Dennis Smith Jr. in a statement Tuesday, saying, "Our Knicks family is deeply saddened by the sudden passing of two of our players' close family members. At times like this, we are reminded that life is bigger than basketball. Our thoughts are with them and their families."