A 26-year-old felon pleaded guilty Wednesday to 10 felonies and five misdemeanors for impersonating a police officer to extort sex from a woman and two 15-year-old girls after responding to their online ads for prostitution and escort services.

Julian Tarver, who had previously served nearly five years in prison for a number of crimes, including first-degree arson, threats to bomb and attempted possession of child pornography, was under the supervision of the state Department of Corrections when he committed his sexually motivated crimes in August 2010, according to court records.

Originally charged with four counts of first-degree kidnapping, Tarver — who forced the women and girls to each remain inside his North Seattle apartment for two to five hours — pleaded guilty to four counts of unlawful imprisonment as part of his plea deal before King County Superior Court Judge Jim Rogers.

He also pleaded guilty to three counts of first-degree extortion with sexual motivation; one count of attempted first-degree extortion with sexual motivation; third-degree rape of a child; and third-degree rape of a child with a one-year sentence enhancement because he offered one 15-year-old victim money in exchange for sex.

Tarver also pleaded guilty to five misdemeanor counts of first-degree criminal impersonation for pretending to be a law-enforcement officer.

When he's sentenced Feb. 3, Tarver faces a prison term of 12 ½ to 14 ½ years, though prosecutors will recommend he serve the top end of the range.

According to court documents, Tarver found each of his victims online and invited them to his apartment, where he would flash a badge, whip out handcuffs and "arrest" the victim. He allowed two 19-year-old women to leave without having sex with them, though he made one of the women strip in front of him and stole $600 cash, her identification and a pawn slip. Three other victims — the two juveniles and a 23-year-old woman — were raped by Tarver, who at different times claimed to be a police officer, a U.S. Marshal and an agent with the federal Drug Enforcement Administration.

He paid one of the 15-year-olds $200 for sex, then took the money back, telling her the bills were marked, court documents say. He slammed the girl into a wall when she tried to leave, showed her a gun and a Taser, and forced her to have sex with him a second time, the documents say.

Tarver was arrested after employees with one victim's escort agency contacted Seattle police when Tarver tried to arrange a date with another escort, charging papers say. The police investigation led detectives to the other victims; one of the juveniles was identified from photos found on Tarver's computer, court records show.

According to charging documents, Tarver found both of the juvenile victims through ads posted on backpage.com, the online advertising site owned by Village Voice Media, the parent company of Seattle Weekly and a dozen other weekly alternative newspapers across the country.

"Although she advertised herself as being of age, she looked young, and I was expecting that she would be less than 16 years of age," Tarver said about each of the juvenile victims in his plea statement.

Senior Deputy Prosecutor Sean O'Donnell said that while Tarver is responsible for his conduct, the case against him "is Exhibit 1 of the evil of being able to sell girls and young women online."

O'Donnell, who has prosecuted a number of pimps who advertised juveniles on backpage.com, was also involved in negotiating a plea deal with Derek "Big Baby" Caldwell.

Caldwell, 25, advertised two girls, 13 and 17, on backpage.com and pimped the girls from a room at the downtown Sheraton Seattle Hotel earlier this year, according to court records. He pleaded guilty Tuesday to attempted second-degree human trafficking and communicating with a minor for immoral purposes and faces between eight and 10 years in prison when he's sentenced Jan. 20.

Sara Jean Green: 206-515-5654 or sgreen@seattletimes.com