AUGUSTA — Convicted sex offender Robert L. Robinson III was sentenced to two years in prison after pleading guilty to possessing child pornography.

The 35-year-old Augusta man pleaded guilty last month to three counts of possession of sexually explicit material depicting a child under the age of 12. According to an affidavit, police arrested him after they found a few images of child pornography while analyzing 100,000 photos on his computer.

Robinson’s apartment was searched and his computer and other electronic devices seized by Augusta police last year. Officers were acting on a search warrant after numerous central Maine parents complained that Robinson had taken photographs of their children — clothed and in public — while they were shopping at Augusta-area stores and posted those photographs online.

Police said the photographs Robinson took of local children in public and posted on social media accounts were not illegal. But three of the photographs they found on his computers were.

The Maine Computer Crimes Task Force, working with Augusta police, found images on Robinson’s computer — some digitally altered and some not — that showed children “approximately 4 to 6 years old” in sexually explicit scenarios, according to an affidavit written by Sgt. Jesse Brann. Three of those images, considered to be child pornography by police, were the basis of the charges against him.

He was sentenced to two years in prison and, following that, two years of probation on the class C charges, which are punishable by up to five years.

Brann wrote in the affidavit that Robinson expressed in at least one update on his social media accounts that sex with children should be legal. Brann also wrote that Robinson said, while his Northern Avenue apartment was being searched, that he “is attracted to young girls … once a girl reaches puberty.” He also admitted to police there might be child pornography on the seized computers.

Robinson told Brann “he was stupid and believed nights when he was intoxicated by alcohol and narcotics that he looked up websites he shouldn’t have.” Those sites, Robinson explained, were hosted on the “dark web” and included chat groups that talk about pedophelia.

His alleged photographing of girls in the Augusta area prompted approval of a law by the state Legislature, sponsored by Sen. Matt Pouliot, R-Augusta, a member of the House of Representatives at the time. The bill made it illegal for sex offenders who have been convicted of sexual assault or sexual exploitation of a child under 14 years old to photograph any child under 14 if the offender has been warned not to do so by a law enforcement, corrections or judicial officer.

Robinson is a lifetime registrant on the sex offender registry. He was sentenced in 2006 to serve an initial six months in prison, with the remainder of the five-year sentence suspended, and four years probation on three counts of sexual assault on a child younger than 14, according to the Maine Sex Offender Registry. Those convictions prohibit Robinson from “intentionally or knowingly initiating direct or indirect contact” with children under 14, the arrest affidavit read.