CHICAGO (CBS) — Authorities think a fire that injured six people late Wednesday night in the South Shore neighborhood might have been deliberately set.

WBBM Newsradio’s Bernie Tafoya reports the fire was in a 50-unit apartment building in the 7100 block of South Jeffery Boulevard.

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A fire official said the fire was mostly contained to one apartment and a hallway.

Six people were hurt, and several people had to be rescued from the four-story building, because they could not get out on their own.

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The Fire Department said it is investigating the fire as suspicious, based on what witnesses have told authorities.

Police said one man injured in the fire said his girlfriend set his couch on fire after the two of them started to fight.

The Police Bomb and Arson Unit also was investigating.

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Four of the people who were hurt were hospitalized in good condition; the other two were in serious condition.