At least 14 people – including three children – were shot in a drive-by shooting Monday night at a busy corner in Chicago where people had gathered for a vigil, and investigators are trying to find the shooters, police said, CNN reported. Two people traveling in a dark SUV opened fire on Halloween night at people on the corner of California Avenue and Polk Street around 9:30 p.m. before the vehicle was driven away, police said. A 15th person – a woman – suffered scrapes when a vehicle struck her as she tried to flee from the site, police said.

A 3-year-old boy, an 11-year-old girl and a 13-year-old boy were among those shot, police said.

Gunshot victims were being treated at hospitals. Their conditions were described as critical for two, serious for five, good for six, and unknown for one, police said Tuesday morning. The vigil was unrelated to the shooting, police said in a news release without giving further details on a motive. People not involved in the vigil may have been at the corner at the time, Chicago Police Superintendent David Brown said in a news conference, according to CNN. “There may have also been others gathered for other various reasons,” he said. “It’s a very, you know, common corner where people congregate and have different meetings and gatherings.” More than 500 mass shootings have happened in the United States so far this year, according to the non-profit Gun Violence Archive. The count was at 574 as of Tuesday, an average of more than 1.8 mass shootings every day, says the group, which like CNN defines a mass shooting as one in which at least four people are shot, excluding the shooter. Also Monday night, a teenager was killed and six others were injured in a shooting at a Halloween party in a home in Kansas City, Kansas, police said. As many as 100 teenagers were at the home when the gunfire erupted, CNN reported.