UPDATE: According to the state's attorney, the case against Kaylan Mukherjee was dismissed.

Thirteen people tied to a prostitution ring have been arrested following a month-long investigation by the Greenwich Police Department that ended with an undercover sting operation over the weekend, police said.

The investigation targeted escorts advertising their services online and men who solicited sex by contacting undercover officers after they posted fake advertisements.

"It is a widespread problem throughout this area that is not specific to Greenwich," said Capt. Mark Marino, who oversaw the crackdown. "These individuals will travel to other towns, and it seems to be a pretty significant problem because it didn't take any time to get people to show up, whether it was a prostitute or a john."

Police began to probe the illicit activities after narcotics officers received a tip from the Stamford Police Department's Narcotics and Organized Crime Squad regarding a prostitution organization operating in Greenwich. Police said they discovered several websites featuring women advertising sexual acts in exchange for money that specifically marketed Greenwich locations. One website featuring Asian women claimed they had offices in Greenwich, police said. Marino would not name the websites, but noted that none of the women were advertising on Craigslist.com, a site that has been frequently used to solicit erotic services.

On April 12, undercover officers arranged to meet with numerous women they communicated with online at the Delamar Hotel. During the meeting, two men drove four females to the hotel to perform the arranged sexual acts, police said. All six were arrested on scene, police said. The women appeared to be catering to an "upscale" clientele as they charged rates as high as $400 an hour, police said.

The drivers were involved in the deal, but are not believed to be pimps, Marino said.

"It is obvious that a lot of those women are working for people higher up the food chain, but there is nobody that we've identified at this point," Marino said.

After completing the first sting operation, police flipped their target and began seeking men who were soliciting prostitutes online. On Friday, detectives obtained hotel rooms at the Hyatt Regency Greenwich and placed ads online offering sexual acts in exchange for money, police said.

The undercover officers were contacted by multiple men who agreed to meet at the hotel for sex, police said. When the men arrived at different times throughout the night, they were arrested.

Marino said the police department decided to aggressively pursue this operation to send a message that prostitution will not be tolerated.

"This type of activity leads to a lot of other crime and is something that we want to drive out of Greenwich," Marino said. "People should think twice about coming here to engage in this type of activity."

Police said both prostitutes and the men who solicit them put themselves at risk every time they meet with a stranger for a sexual encounter.

"You don't know who is coming through that door, and it could lead to a very dangerous situation," Marino said.

During the first phase of the operation, police charged Jasenia Chabron, 21, of Brooklyn, N.Y., with prostitution, conspiracy at prostitution, possession of narcotics and possession of drug paraphernalia; Daniel Vrabec, 51, of 440 W. 34th St., New York, with promoting prostitution and conspiracy at prostitution; Jessica L. Putzig, 29, of 41 Manor St., Stamford, with prostitution; Antoine Odums, 30, of 111 Chapel St., New Haven, with promoting prostitution and conspiracy at prostitution; Rosaida Llerena, 22, of 111 Chapel St., New Haven, with prostitution and conspiracy at prostitution; and Haiyan Lu, 33, of 13265 Avery Ave., Flushing, N.Y., with prostitution. Police said Chabron was found in possession of heroin and packaging material.

Odums, Chabron and Vrabec were charged with felonies, while the rest of the defendants were charged with misdemeanor crimes.

During the second phase of the investigation, several men were charged with patronizing prostitutes, including Francis W. Hogan III, 50, of 52 Father Peters Lane, New Canaan; Alexander G. Huebner, 19, of 7 Shady Brook Lane; Joseph Tarnowski, 54, of 46 Mabel Ave., Danbury; Edward Gangi III, 28, of 500 Bedford St., Stamford; Ronal A. Paredes, 24, of 114 Ludlow St., Stamford; and Kaylan Mukherjee, 41, of 164 Cat Rock Road.

Hogan is the senior vice president at Silgan Holdings Inc., a consumer goods packaging company, according to the company website. Huebner is a recent graduate of Greenwich High School, according to records.

Also on Friday, police charged Nieda L. Ponce, 43, of 175 Prospect St., Stamford, after finding an advertisement online and arranging a meeting while staking out the Hyatt, Marino said. Ponce was charged in a similar incident in Bridgeport in 2009, according to court records.

Everyone charged was released on a promise to appear following their arrests. Some of the defendants have already appeared in state Superior Court in Stamford. Others will be arraigned on May 13.

Police said they could not disclose those arrested on April 13 because the sting was part of an ongoing investigation that ended on Friday. Police do not believe either hotel had any knowledge of the alleged prostitution ring. Messages were left with representatives for both hotels.

Staff writer Debra Friedman can be reached at debra.friedman@scni.com or 203-625-4449.