WILLINGBORO, N.J. (CBS) — The mother of a Willingboro High School senior who was shot and killed outside his home last night is speaking to CBS3 about what happened, and what she wants to remember about her son. It comes as police continue to investigate why this honor student and chess player was killed, and who pulled the trigger.

“He was a big ol’ loving bear. Big gentle giant, big ol’ smile,” Saleenah Bell said.

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Less than 24 hours after her son was gunned down in front of their Willingboro home, Yahsinn Robinson’s mother is still coming to grips with what happened.

“I heard gunfire so close. I never in a million years thought it was my kid,” Bell said.

Yahsinn, despite being diagnosed with autism at a young age, was an honor student at Willingboro High School and an avid chess player.

“We worked and worked and worked until he was able to speak well,” Bell said.

Thursday night, the 18-year-old was due home from his part-time job at the Pitney Bowles warehouse in Levittown. His mom scheduled his Uber earlier that day.

“I’m expecting him to walk through the door like he do every day,” Bell said.

Bell called police after hearing shots shortly before 11:30 p.m., then called Yahsinn to warn him.

“He didn’t answer,” Bell said.

She went outside to try to help the victim, still unaware that it was her son.

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“I came out, I noticed his backpack,” Bell said.

That image she says, is one she’ll never forget. It’s also one she hoped to never see after moving her family from North Jersey to Burlington County two years ago.

“I thought it was going to be OK here,” Bell said.

Now, she’s searching for answers as to why and who could do this.

“If they had met him and got to know him, they would’ve never hurt him,” Bell said.

Bell is remembering her first-born, the man with the kind smile affectionately nicknamed Ya-Ya.

“He was at the wrong place at the wrong time but the sad part is that it was home,” Bell said.

Willingboro police and the Burlington County Prosecutor’s Office are looking through Ring camera video in the area to piece together what happened to Yahsinn Robinson.

Anyone with information is asked to give them a call.

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CBS3’s Alicia Roberts reports.