A 42-year-old Newport Beach man was sentenced to five years in prison for his guilty plea Thursday to molesting a 12-year-old girl he met through a social networking site.

Samuel Brent Robertson, who pretended he was 24, was arrested in November 2010 in Ladera Ranch as he was about to meet the girl, Orange County Deputy District Attorney Jennifer Walker said.

After starting the online relationship, Robertson picked up the girl at her middle school in Ladera Ranch in mid-October 2010, Walker said. He drove her to Newport Beach's Back Bay area where he molested her, Walker said.

Walker picked up the girl again on Nov. 1, 2010 and drove her to his house in Newport Beach where he again sexually assaulted her, Walker said. There was another sexual encounter two days later, the prosecutor added.

The victim's mother discovered the text messages between the two and notified Orange County sheriff's deputies.

A message left with defense attorney Allan Stokke was not immediately returned.

Robertson accepted a plea deal from Orange County Superior Court Judge Craig Robison, said Walker, who objected because she thought he deserved more time in prison.

Robertson does not have a prior criminal record, but his plea deal amounts to two strikes, so if he has another brush with the law after being released from prison it could be considered a third strike, which would lead to life in prison, Walker said.

The victim's parents wished Robertson would have received more time in prison, but they were relieved their daughter wouldn't have to testify in a trial, Walker said.

"They would like him to receive more time in prison, but they're happy he's going to prison," Walker said.

Robison allowed Robertson to surrender in 10 days so he could take care of a health issue first, Walker said.

Robertson pleaded guilty to 23 felony counts of luring a child with intent to commit a crime, lewd or lascivious acts with a minor, and meeting a minor to commit a lewd act, according to court records.

Robertson also pleaded guilty to a misdemeanor count of disobeying a court order because he contacted the victim after his arrest, Walker said.