RIVERSIDE (CNS) - Additional charges were filed Friday against a San Diego County businessman accused of molesting three young boys and raping a woman in Riverside County -- with more allegations possible, a prosecutor said.

"This is a huge investigation," Deputy District Attorney Will Robinson told City News Service. "It has expanded since it began, and it may grow."

Richard James Sears, 47, of Escondido was arrested Aug. 29 following a Riverside County sheriff's investigation into child sex abuse allegations going back to 1999.

Sears was initially charged with six felony counts, but during a hearing today before Superior Court Judge Helios Hernandez, Robinson submitted an amended complaint, adding 13 new charges, including forcible rape, lewd acts on a child under 10 years old, sodomy of a minor, sexual penetration with a foreign object and a sentence-enhancing allegation of targeting multiple victims during a crime series.

Most of the charges stem from the defendant's alleged contact with three boys -- identified in court documents only as John Does 1, 2, and 3 -- in the early 2000s. However, one count alleges rape of an adult female, identified only as Jane Doe in court papers.

According to the complaint, the alleged assault happened within the county in 2011, though the specific location and circumstances weren't disclosed.

Robinson said Sears is not related to any of the victims. The prosecutor declined to provide further details.

Sears is a software development professional and owned a dotcom, selling it for a substantial profit, according to investigators.

The defendant's San Diego attorney, Paul Pfingst, argued today for Hernandez to lower Sears' $5 million bail, citing the defendant's lack of prior criminal history. But the judge deferred a decision to give the prosecution an opportunity for rebuttal on Oct. 2.

Sears is being held at the Smith Correctional Facility in Banning.

According to sheriff's Sgt. Glenn Williams, investigators were contacted Aug. 6 regarding "multiple child molestations" that court documents indicate allegedly occurred more than a decade ago. Detectives spoke with two alleged victims and began gathering evidence in support of an arrest warrant, culminating in the defendant being taken into custody at his residence, Williams said.

Sears has no prior felony convictions.