An 11-year-old boy shot and killed a teenager who was allegedly trying to break into his home in Missouri on Thursday.

St. Louis County police say that a 16-year-old boy, identified as Lamonte Streeter, and a 22-year-old man allegedly tried to break into a home north of downtown St. Louis twice on Thursday afternoon, reports The Associated Press. After two unsuccessful tries, authorities said the teen went through the home's unlocked front door while only the 11-year-old and his 4-year-old sister were home alone.

That's when the 11-year-old boy used a handgun to fire one shot into the teen's head. Meanwhile, the second suspect fled the scene but was later taken into custody.

Witnesses, on the other hand, don't believe that account. Neighbors say that the teenager, who lived just blocks away from the murder scene, was not trying to break into the home. Rather, the teen was shot at point-blank range as the two were talking near front door, they said.

"It was not a break-in," neighbor Donna Jackson, 45, told the St. Louis Post-Dispatch. "He shot him in the head."

Jazmyne Clark, 18, who lives two doors down from the shooting, said the 11 year old was on the front porch and told the 16 year old to approach him. Once the teen reached the front door, the younger boy shot him, Clark said.

"He was never in the house. He wasn't breaking in at all. He was just trying to sell him his phone," Clark told the newspaper.

A relative named Sharon Taylor, who lives next door, described the boy as a troublemaker. She also expressed doubt about the break-in story, noting that a home invasion is unlikely to happen in the daytime.

Police are now questioning why the children were left home alone in addition to how and why the 11-year-old boy had access to a gun.

Police believe the mother purchased the handgun after other home break-in attempts, reports Fox2Now. St. Louis County police spokesman Sgt. Brian Schellman said she is cooperating with the investigation.