CASPER, Wyo. — A 20-year-old woman arrested in September and charged with two felony counts of promoting prostitution has pleaded not guilty to the charges.

Amber Crystal Mefferd entered her pleas during a brief arraignment before Natrona County District Judge David Park on Wednesday morning.

She was arrested Sept. 30 at the Parkway Plaza Hotel and Convention Centre after allegedly agreeing to have sex with another woman and a man in exchange for $500. The man was an undercover officer, according to authorities.

The woman police said she agreed to perform sex acts with -- 23-year-old Alyssa Jurado -- was also arrested. She pleaded guilty to one misdemeanor count of prostitution and was fined $490.

According to previous courtroom testimony, investigators with the Casper Police Department had been monitoring ads on a website called during the days leading to the women's arrests. After a series of email exchanges, text messages and phone calls between an undercover officer and "Ashley," a tryst between "Ashley," "Callie" and the undercover officer was scheduled, police say.

Authorities say they later determined that "Ashley" was Mefferd and "Callie" was Jurado.

On the night of the scheduled tryst, the women walked into a hotel room and kissed the officer on the cheek. They then discussed a dollar amount and came to $500, or $250 for each woman, police say.

The undercover officer put $500 beside Mefferd's purse, the women got undressed, climbed onto a bed and began sex acts, according to previous courtroom testimony.

They were then arrested. Investigators used video surveillance equipment to monitor the situation from an adjoining room, according to an arrest affidavit from the case.

Authorities allege that Mefferd introduced Jurado and another woman into prostitution.

Apart from two counts of promoting prostitution that each carry a maximum possible penalty of five years in prison, Mefferd also faces a misdemeanor charge of prostitution. That charge carries a maximum penalty of six months in jail.

The other woman police say Mefferd was working with is 18-year-old Kelly Birgenheier, who was arrested at the Parkway Plaza the same night after allegedly having sex with a john at the hotel. She has pleaded not guilty to a single misdemeanor count of prostitution and has a trial scheduled for December.

Mefferd's trial is tentatively scheduled for January. She remains free on $3,000 bond.