*Two suspects have been arrested in the killing of a 5-year-old boy shot in the head while in the backyard of a South Los Angeles home as he prepared for Halloween, police said.

Aaron Shannon Jr. (above)  ran into the backyard to show off his Spider-Man costume (see below) Sunday to family when two men armed with handguns opened fire in the alley behind the home, striking the boy in the back of the head.

Marcus Denson, 18, was arrested Thursday at a home near the killing site after a brief chase, Los Angeles police Capt. Dennis Kato said.

Leonard Hall Jr., 21, was arrested at about 2 a.m. Friday at an apartment building several miles north of the site, Kato said.

The men, both reputed members of a local street gang, were booked on suspicion of murder and remained jailed Friday, he said. Their bail was set at $1 million each, according to the Los Angeles County Sheriff’s Department.

“We knew, as a law enforcement agency, that eventually we were going to get these guys,” Kato.

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Aaron Shannon Jr. in his Spider-man Halloween costume