Prosecutors in Chicago are offering little explanation for why they dropped charges against one of four teens accused of beating an honor student to death last month.

In a statement, the Cook County state's attorney's office says "additional information has developed" that led to the dismissal of charges against 18-year-old Eugene Bailey on Monday.

A spokeswoman for the office declined to elaborate, saying the investigation is ongoing.

Bailey was charged with first-degree murder in the Sept. 24 beating of Derrion Albert.

A cell phone video shows a group striking Albert with boards and kicking him as he lay on a sidewalk. Albert was a sophomore at Christian Fenger Academy High School.

Three other teens are facing charges. Their next court date is Friday.

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