Police arrested a 42-year-old man on suspicion of second-degree murder after a 30-year-old woman was found dead Friday in a Waikiki hotel room.

At a news conference at the main station, the Honolulu Police Department provided few details on the death, including what the relationship between the two was.

However, a police source told the Honolulu Star-Advertiser that the man is from the mainland doing work in Hawaii and that the woman was a prostitute.

Officers responded to a 4:17 a.m. call Friday for a person in need of medical assistance and found the woman’s body at a Kuhio Avenue hotel room. The case was initially classified as an unattended death.

However, “based on the investigation at the scene, they determined there was enough to support a murder second arrest,” said Capt. Walter Ozeki of HPD’s Criminal Investigation Division.

Police arrested the man at the Hilton Waikiki Beach Hotel, 2500 Kuhio Ave.

Ozeki declined to say anything about injuries, whether any weapons were used, who called 911 or where the suspect is from.

HPD this week discontinued the long-standing practice of providing suspects’ home addresses on its booking logs.

The Honolulu medical examiner’s office had not identified the woman Friday or provided a cause of death.

A Hilton spokeswoman declined to answer questions on the death.

“Unfortunately, it’s one of many incidents, which just so happens to be publicized,” said Kathryn Xian, founder of Pacific Alliance to Stop Slavery, which advocates strict enforcement on johns and pimps/traffickers. “It’s a common occurrence in the industry.”

Prostitutes “get it from both sides — the johns and the pimps,” she said.

While some are psychotic and can kill, all johns share the belief that “it’s OK to purchase a human being for their body, thereby dehumanizing a human being for the purpose of sex,” Xian said. “That’s a commonality, an abnormal behavior.”

Prostitutes often start off as runaways or abused kids recruited by a trafficker with a promise of a better life and often overdose on drugs or are found dead, she said. A pimp will retaliate if a prostitute disobeys him.

There is a misconception that “pimps or traffickers protect the girls, but usually pimps only come in when the john doesn’t pay, not when the john hurts or murders the girl,” Xian said.

Xian referenced the case of Ivy Harris, the 28-year-old murdered in May 2013 in Waikiki by a john, Marine Master Sgt. Nathaniel Cosby. “Ivy had a pimp, and he was part of a big ring in the Pacific Northwest, and they couldn’t stop what happened to her.”