SAN FRANCISCO — On a website called Azerbaijani Eagles, you can commission a murder for $5,000. The site Slayers Hitmen provides more options, with a beating going for $2,000. Death by torture costs $50,000.

But don’t expect someone to get the job done. Experts and law enforcers who have studied these sites — almost all of them on the so-called dark web or dark net — say they are scams. There has not been a known murder attributed to any of them.

That doesn’t mean the sites aren’t involved in a very dark trade. They have become catch points for real people who are looking to pay to have someone murdered. And a number of men and women are sitting in jail after paying one of these sites — and getting caught by the police.

In one of the most recent cases to make its way through the courts, a nurse from Illinois was sentenced to 12 years in prison after pleading guilty to sending $12,000 in Bitcoin to the site Sicilian Hitmen International Network. She had hoped to have the wife of her boyfriend killed.