A two-month investigation in the Suffolk County Grand Jury led to additional charges against a Quincy man already accused of sexually assaulting a 5-year-old girl in his care, District Attorney Daniel F. Conley announced today.

In a six-count indictment returned May 6, SERGIO LARA (D.O.B. 7/10/57) is charged with rape of that 5-year-old child, indecent assault and battery on a second 5-year-old child, and two counts each of disseminating matter harmful to minors and open and gross lewdness for incidents involving two boys, ages 8 and 9. He was arraigned on those charges this morning in Suffolk Superior Court and held without bail pending a bail review sought by his attorney.

Revere Police arrested Lara on March 2; he has been in custody since that time. He is the owner and operator of Maya Transportation, which shuttles children to and from schools and day care centers in Revere, Chelsea, and East Boston.

Speaking at this morning’s proceedings, Assistant District Attorney Mindy Klenoff told Clerk Magistrate Gary D. Wilson that Lara first came to authorities’ attention in early March after the first victim disclosed the abuse to her mother.

In that case, Klenoff said, Lara picked the girl up from day care on the afternoon of March 1. After driving the other children home, he allegedly drove her to an undisclosed location and sexually assaulted her. He then allegedly instructed her not to tell anyone what had happened and promised he would buy her favorite candy the next day. He then drove the girl home.

The girl reported that assault to her mother, who took her to the hospital and notified Revere Police and the day care provider. Revere detectives began their investigation and the day care provider suspended Lara.

The next day, the mother of another 5-year-old girl who rode Lara’s minivan learned of the allegations.

“Taking care not to mention the defendant’s name,” Klenoff said, the mother asked her daughter if anyone had touched her private parts. The girl responded that Lara had done so and that she didn’t like it. That mother also reported the abuse to police.

During the course of the investigation, Klenoff told the court, prosecutors learned of two young brothers who rode in Lara’s van separately. Both told authorities that he had shown them pictures of naked women on his cell phone and had masturbated in front of them in the minivan.

Kathryn DiPerna is the DA’s assigned victim-witness advocate. Lara is represented by attorney Christopher Coughlin. His next scheduled court date is on July 15.