Published: Apr 04, 2011 8:43 PM EDT
Updated: Apr 04, 2011 5:43 PM EDT

TAMPA, Fla. - A Tampa Bay-area man who spent 18 years in prison on a rape conviction is expected to walk free on the strength of new DNA evidence.

Prosecutors in Bradenton said Monday they will drop charges against Derrick Williams after a state circuit judge overturned his conviction and prison sentence last week.

The same gray T-shirt that helped put Williams in prison for life in 1993 resurfaced as the piece of evidence that led to the conviction being thrown out. A DNA expert found it "highly unlikely" that Williams wore the shirt because there was DNA on it from other people but not from Williams.

State Attorney Earl Moreland said he still believes Williams is guilty but time and legal hurdles make it difficult to prosecute the case again.

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