Two people were killed and several people were injured Friday morning when a gunman opened fire during a street party with thousands of parties celebrating Halloween in Orlando.

Officers quickly arrested a 17-year-old male suspect, Police Chief Eric Smith said during a briefing. Authorities have not yet determined a motive.

The gunman fired into downtown Orlando’s bar and restaurant district around 1 a.m. Officers responded as costumed revelers fled, and the same gunman fired again about a block away, Smith said.

Here’s what we know about the victims:

A total of nine people were taken to Orlando Regional Medical Center. The two men who died were 25 and 19 years old. Their names have not been released.

The other victims are:

• an 18-year-old man, shot in the left leg
• a 39-year-old woman, shot in the left hand
• a 24-year-old woman, shot in the left leg
• a 20-year-old man who suffered a head injury
• a 26-year-old man, shot in the right leg
• a 19-year-old woman, shot in the upper back, stuck in the cheek
• a 26-year-old woman who suffered injuries from being trampled on

A tenth victim was treated after being trampled by the crowd as people fled.

One of the Halloween revelers killed and another who was injured were students at the University of Central Florida, the school said in a statement Friday.

The shooting “may have affected many students who were celebrating Halloween and in the vicinity of the incident,” the university said. “Our thoughts are with all the loved ones affected during this unimaginable time.”