A Bainbridge Island man accused of child rape will plead guilty to a lesser charge, in a deal reached Thursday in Kitsap County Superior Court.

David Alan Nusbaum, 40, was slated to stand trial this week on charges of first-degree child rape, for offenses against the daughter of his then-girlfriend over a six-year period beginning when the girl was age 6.

Instead, he will plead guilty to felony third-degree assault with sexual motivation, prosecutors said.

Nusbaum did stipulate to the facts as presented in charging documents, prosecutors said. If he does not comply with terms of the plea agreement, he will be found guilty of rape of a child in the first and second degree and child molestation, which could lead to a sentence of 20-28 years.

Prosecutors say their case was hobbled by a civil lawsuit already filed by the victim’s mother against Nusbaum, who is the beneficiary of a large family trust.

That civil action would damage the credibility of the accuser at trial, and was one of the factors that led county Prosecutor Russ Hauge to abandon the case.

“We came to the conclusion that there were serious ‘proof problems’ with this case,” said Claire Bradley, senior deputy prosecuting attorney.

Nusbaum, who has been jailed in Kitsap County since last April following his arrest in Florida, was released Thursday. He is being given credit for time served, and will not serve additional jail time.

Nusbaum will be required to register with the Kitsap County Sheriff’s Office as a sex offender, at which time, depending on his presumed likelihood to reoffend, his address may be made available to the public through a register of offenders.

Bainbridge police and school officials met with neighbors in the 5100 block of North Tolo Road Friday morning, at a school bus stop near where Nusbaum is said to maintain a residence.

Nusbaum still could be charged with alleged crimes against the same victim in King County, Pennsylvania and Florida, Bainbridge Police Detective Scott Weiss said.