Tyshawn Lee seen in a Facebook posting.

Story highlights

NEW: "Please put the guns down, please," boy's mother begs

NEW: She asks anyone with information to step forward

Police don't have a motive; unsure if the child was targeted

CNN  — 

A 9-year-old boy was shot and killed Monday in Chicago and police say it isn’t clear whether the child was targeted or was in the wrong place at the wrong time.

Tyshawn Lee loved to play basketball and video games. On Monday he was in an alley in the Gresham neighborhood, according to Chicago police. Witnesses said an argument broke out and that’s when the boy was shot.

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Tyshawn was hit multiple times in his upper body and died in the street.

Mourners placed stuffed animals and a basketball in the alley where 9-year-old Tyshawn Lee was shot to death.

Investigators haven’t been able to discern a motive for the slaying, Chicago police detective Dean Andrews said at a news conference, adding, “We will be working around the clock to find out more.”

Visibly distraught, the boy’s mother, Karla Lee, spoke to reporters Tuesday. She asked anyone with any information about the shooting to step forward. She held a photograph of her son and a football.

“Please put the guns down, please,” Lee begged between tears. “I’m only 26. This is my only baby.”

A small memorial with stuffed animals and a basketball appeared in the alley where the boy was killed.

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As detectives canvassed the area and interviewed neighbors, saddened and outraged residents were determined to do what they could.

Some handed out fliers asking anyone with information about Tyshawn’s killer to contact police. The flier said a reward would be given.

Crisis responder Dawn Valenti told reporters that donations for that reward had reached $20,000 as of Tuesday evening.

Tyshawn’s death happened on the same day Democratic presidential candidate Hillary Clinton met in Chicago with parents whose African-American children have died in shootings.

The Chicago Tribune allows readers to compare violence in each neighborhood and updates shooting incident data several times a week. As of Tuesday, 2,578 had been shot since January 1, 2015.

That’s compared to 2,587 who were shot between January 1 and December 31, 2014.

September was the deadliest month since 2002 for gun violence, the newspaper reported. The city recorded 60 homicides that month.