Online prostitution has seen disturbing growth in the past half-decade and, even more disturbing, the age of those arrested is dropping, according to an investigative sergeant with a special investigations unit in Dublin.

Sgt. George Lytle offered a deeper view into a prostitution sting that netted a dozen arrests on prostitution-related charges in late March at a Dublin hotel that police did not wish to identify.

Lytle said such stings are conducted in collaboration with the Alameda County Sheriff's Department and Sexual Assault Felony Enforcement (SAFE) Task Force about every month throughout the county.

Authorities rotate areas that are targeted based on how prevalent the online prostitution is in a given place, according to Lytle.

"One operation might focus on Tri-Valley, another may focus on Castro Valley," he said. "Our investigators look every day online for possible leads and follow where those take us."

Although Craigslist has grabbed most of the headlines related to online prostitution, Lytle said other websites such as My Redbook and Eros also see heavy traffic. 

In the March 30 operation, none of the dozen arrested were Dublin residents. Lytle said the suspects were from other East Bay cities such as Hayward, Vallejo and Oakland and had come to Dublin to meet with online clients.

Lytle said that is the trend in such police stings.

"Most of them come from the East Bay, with a lot from Oakland, Vallejo, Hayward," he said. "It's not really the type of investigations where we drive down the street and arrest them there anymore."

Lytle said he remembers online prostitution ramping up in 2004 and has seen it continue to grow. He added that investigators are seeing more juveniles advertising online.

"Sadly, we're seeing more young girls being preyed on to put themselves online or they think it's safer to do it that way," he said.

Dublin-area hotel managers often serve as leads for police tracking prostitutes, according to Lytle, who added that police still have problems tracking clients.

"Our businesses here are really good about reporting possible prostitutes and call us whenever they see strange activity going on," he said. "But our problem is still with people coming in, getting a room and calling in a prostitute from there."

Lytle said varying the frequency and location of stings helps curb the crime.

"We want to keep people skittish about it," he said.