PIERRE - A Martin man serving a life sentence must get a new trial on charges he raped an 8-year-old girl, the South Dakota Supreme Court ruled Thursday.

The high court unanimously threw out Fred Packed Jr.'s convictions for rape and sexual contact with a child because the judge in his first trial prevented the defense from asking questions about whether the girl had a motive to falsely accuse him.

Packed was accused of molesting the girl during June 2003, when the girl lived with her grandmother and Packed in a house in Martin.

A jury convicted Packed of first-degree rape of a child younger than 10 and sexual contact with a child younger than 16. He admitted he was a habitual offender and was sentenced to life plus 25 years.

Packed argued he was denied a fair trial because his lawyer was prevented from asking a law officer, the girl's mother and the girl's grandmother about a neighbor boy alleged to be the girl's boyfriend.

The defense contended the girl was worried she would get in trouble because of the alleged boyfriend, so she fabricated the allegations against Packed to deflect attention away from her possible relationship with the boy.

Circuit Judge Kathleen Trandahl ruled that such evidence would not be allowed in the trial because she believed Packed was trying to offer evidence that the boy had committed the crimes. A defense lawyer said he was not suggesting that the boy committed a crime, but was instead exploring whether the girl made up allegations against Packed to shift attention away from her possible relationship with the boy.

The Supreme Court said Trandahl erred in preventing the defense lawyer from questioning witnesses about the alleged boyfriend. Excluding all references to the boy probably violated Packed's right to a fair trial, the justices said.

Evidence that could establish a motive for the girl to make up the allegations against Packed was relevant because it would cast doubt on the state's evidence that Packed committed the crimes, the high court said.

The state also had agreed to limit the time frame to allege that Packed committed the offenses on or between June 6 and June 9 of 2003.

Because of that agreement, the judge erred in giving the jury instructions that said he could be convicted if jurors believed beyond a reasonable doubt that the offense was committed on a date reasonably near the alleged date, the Supreme Court said.