A male nanny who is accused of molesting numerous children who were under his care is now facing additional charges, officials said Friday.

Matthew Antonio Zakrzewski, 30, of Costa Mesa, allegedly victimized 12 boys between the ages of 4 and 10, according to the Orange County District Attorney’s Office.

Zakrzewski was arrested on May 17 after getting off an international flight.

He was initially charged with three counts of lewd and lascivious acts with a minor under 14, one count of oral copulation of a child under 10 and one count of being in possession of child pornography.

Zakrzewski pleaded not guilty to the original charges in May and is being held on $1.25 million bail.

He now faces a total of 25 charges that also include using a minor for sex acts and distributing pornography to a minor for the purpose of engaging in sexual conduct

The crimes allegedly occurred between January 2016 and May 2019.

An investigation into Zakrzewski began in May when a Laguna Beach couple reported to police that their babysitter had inappropriately touched their 8-year-old son.

The couple had found Zakrzewski on one of his several babysitting websites.

The investigation led to the discovery of a second victim, a 7-year-old boy, and 10 additional boys across Southern California, officials said.

Additional victims were identified using video evidence and tips from the public. Authorities are asking for the public’s help in identifying possible additional victims.

After pleading not guilty to the new charges, Zakrzewski was scheduled to return to court on Nov. 8.

He faces 490 years in prison if convicted as charged.

“These parents were led to believe that they could trust this man with the most precious thing in their entire world – their children,” Orange County District Attorney Todd Spitzer said in a news release Friday. “Instead, he preyed on these innocent boys and violated that trust in a vile and sadistic way.”