LOCKPORT - David J. Grover, who kidnapped a 5-year-old girl from her North Tonawanda home last summer and sexually abused her, pleaded guilty today after a judge said she probably would allow prosecutors to tell a jury about his past similar crimes.

Grover, 35, of Niagara Falls Boulevard, Town of Tonawanda, agreed to take a 15-year state prison sentence followed by 25 years of probation-like post-release supervision. Niagara County Judge Sara Sheldon Farkas will make it official April 30.

Grover pleaded guilty to second-degree kidnapping as a sexually motivated felony, which lengthened the post-release supervision period and also forced him to register as a sex offender after he is released from prison.

The girl’s great-grandmother told reporters that was important “so he can’t hurt anyone else.”

Assistant District Attorney Robert A. Zucco said if the case went to trial, he and Deputy District Attorney Holly E. Sloma should be allowed to tell jurors about Grover’s 2007 conviction for taking another small North Tonawanda girl on a car ride for several hours without permission.

There was no evidence of sexual abuse in that case, but Zucco said, “It was a remarkably similar offense.”

Defense attorney David C. Douglas said allowing that would sink Grover’s hopes of acquittal.

“I think the prejudicial impact is insurmountable. The trial is over before it starts,” Douglas said.

When Farkas said she was inclined to let the prosecutors introduce information about the 2007 incident, she also asked if there was any chance of a plea today. Douglas asked for time to talk to Grover, and the plea deal was worked out in about half an hour.