(CNN) Seven children under the age of 17 have been killed by gunfire in St. Louis this year, police told CNN.

The most recent victim is Xavier Usanga, just 7 years old, who was shot and killed Monday while he and his sisters played in the backyard of their home in the city's Hyde Park neighborhood, police said. A person was taken into custody Wednesday in connection with the shooting, police said.

Xavier, Dawn Usanga's youngest child, was supposed to start second grade at Clay Elementary the next day, his mother told CNN affiliate KTVI . Her only son's illuminating smile will be missed.

"He affected a lot of people in the community. He was a really great little boy," his mother said through her tears.

Two men were shooting at each other in the street when her child became another of the city's innocent victims of gun violence, she explained. "The bullet went through my son's throat and then grazed my daughter's elbow," Usanga told KTVI.

An 18-year old was also critically wounded during the summer night gunbattle, according to Major Mary Warnecke , deputy commander of investigative services for the St. Louis Metro Police Department.

Warnecke did not conceal her anger when she took her message to the streets on Tuesday, holding a news conference in Xavier's neighborhood. She said that four children under the age of 10 have died in the area this year alone and noted that the questionable deaths of other children are still under investigation, so that number might be even higher.

"Been doing this a long time and there's a line that used to be -- you don't hurt a child," she said. "And that line's been crossed too many times. And I know people have information and they're not coming forward. It's shocking."

Children dying in the streets is "not the norm," said Warnecke. "I don't want our region to be desensitized to this."

An unwanted ranking

In 2017 (the FBI's most recent statistical year), St. Louis had 66.1 murders per 100,000 people. By comparison, the overall nationwide statistic was 5.3 murders per 100,000 people in 2017, according to the FBI.

This familiar story is being told once again by the most recent crime statistics published by the St. Louis Police Department . Murder and assault rates have increased in the first seven months of 2019 in the city, as compared to the same period in 2018.

Homicides in St. Louis year-to-date number 114, compared to 105 at this same point last year -- an 8.6% uptick. A 6.4% increase in aggravated assaults has also occurred over the same time period: 2,327 gun, knife and other assaults happened year-to-date compared to 2,188 last year. Rape, including attempted rape, decreased by 22.7% from last year in the first seven months of 2019.

Overall, though, the St. Louis Police Department reports that total person crime has increased by 3.6% so far this year.

Not just a statistic

Numbers are meaningless to the mother of a child who's been killed. Dawn Usanga wants the person responsible for Xavier's death brought to justice, she told KTVI.

Clay Elementary School students brought a letter home Tuesday evening to inform their parents of Xavier's death. St. Louis Public Schools spokeswoman Meredith Pierce told CNN that a crisis team was at the school.

"A crisis team is sent to a school whenever a tragedy occurs. The team provides services to students, staff and family. The team is made up of counselor, social workers, and nurses," Pierce said. "Unfortunately we've had a violent summer."

President of St. Louis' Board of Aldermen Lewis Reed said in a statement on the day following Xavier's death that he would be drafting a "local ordinance relating to gun purchases" in the city.

"Today, another family in the City of St. Louis woke up having to face the reality that they will have to plan a funeral for their child... I am outraged that we are still holding on to the same old ways that no longer work to address the issues of crime," tweeted Reed

Warnecke also blames gun violence for the recent child homicides, yet her focus, for now, is on Xavier's death.

"It's a small neighborhood. People know each other. They know who come and go, more than we do. I know people know who shot and murdered these children. I know for a fact people know who is responsible and we are not getting the calls we need. We are not getting people knocking and demanding that we arrest these people," she said.

While it's clear Xavier "was murdered in front of his siblings... we're still piecing together what happened," said Warnecke.

Asked whether the children should not have been outside after the city's curfew, Warnecke reacted angrily: "None of these children are to blame. We can enforce a curfew and one is in place but the children are not to blame." Instead, the community needs to step up, she said. "I am saddened that we haven't had the cooperation and information we need."

Correction: An earlier version of this article indicated there have been seven child deaths by gunfire in St. Louis since June. That number is for all of 2019. This story has been updated to clarify that the seven deaths occurred in the city of St. Louis.