CHICAGO (AP) _ Police have recruited additional officers to investigate the killing of 11-year-old Ryan Harris after charges were suddenly dropped against two young boys.

The extra officers will add ``new visions'' by assisting detectives already involved in the case, Pat Camden, a police spokesman, said Monday.

``It's just bringing in some people who haven't been on the case so they can take an independent look,'' Camden told The Associated Press, adding that the practice is not unusual. ``There was nothing wrong with what was originally done.''

Investigators lost time while they built a case against the boys, ages 7 and 8. The two allegedly confessed to molesting and murdering Ryan in July, but were virtually ruled out as suspects last Friday after semen was found on Ryan's underpants.

Camden said detectives often solve cases that are months or years old.

Police want to talk to a man known as ``the toy guy,'' who reportedly began giving the 7-year-olds toy cars and trucks almost immediately after Ryan's body was found July 28.

Defense attorneys for the 7-year-old said the boy saw the ``toy guy'' on the street recently and told his mother that the man had struck Ryan.

Prosecutors have come under fire since they announced last week that they were dropping their case because of the semen evidence. Medical experts said the chance of boys that young producing semen is remote.

Defense attorneys and the boys' parents have criticized authorities for building a murder case based solely on the alleged confessions of the two small children made to police with no relatives or lawyers present.

Critics are asking why police didn't put more stock in three witnesses who said they saw the victim with a strange man the night she disappeared, and why it took weeks until the tests found the semen on the girl's underpants.