An Illinois man was arrested on Tuesday in the dismemberment murder of a toddler whose body parts were found in a Chicago lagoon more than a year ago, police said.

Kamel Harris, who was caring for 2-year-old Kyrian Knox and reported him missing in September 2015, was taken into custody on suspicion of murder, concealment of homicidal death and dismembering a human body, Chicago police officials said.

Evidence against Harris includes the boy's blood found in the carpeting of his vehicle as well as statements from witnesses, Chicago Police Commander Kevin Duffin told reporters at a news conference.

Duffin said investigators believe Harris, of Rockford, "snapped" and killed the child, who was lactose intolerant, because he had been crying after drinking milk.

"A major break in the case was the fact that he had denied that the baby had ever been inside his vehicle," Duffin said, which contradicted the finding of blood evidence there.

Parts of the boy's body were recovered from a lagoon in Chicago's Garfield Park over Labor Day weekend in 2015.

Harris, who was caring for Knox while his mother moved to another state, later reported him missing, police said. The cause of death for the boy has not been determined.

(Reporting by Tim McLaughlin in Chicago and Dan Whitcomb in Los Angeles; Editing by Lisa Shumaker)