A federal grand jury last week indicted two men on charges they tried to murder a man they thought was talking to the feds about the sex trafficking ring one of them allegedly ran.

Raymond Jeffreys, 27, of Dorchester, had already been charged as a ringleader of the alleged operation, which federal officials say hired out women and teens in hotel rooms from Maine to California between 2006 and 2014.

A superseding indictment issued last week accuses him of ordering Jaquan Casanova, 24, also of Dorchester, to murder Darian Thomson, who had allegedly helped run the ring, but whom the feds say Jeffreys thought had started talking to investigators.

According to officials, Casanova shot Thomson in the head as Thomson sat in a car at Draper and Westville streets around 10:10 p.m. on April 30, 2013. Thomson, however, lived.

In addition to being charged with the shooting, Casanova is also charged with lying earlier this year to federal investigators and Boston police detectives investigating the shooting.

Federal officials allege Jeffreys was one of several men who preyed on vulnerable woman and girls at bus stops or on social networks and turned them into prostitutes, whom they essentially managed to keep imprisoned as they allegedly ferried them from state to state.

According to court documents, the men would sell the women - although most were under 18 at the time - at hotels along highways, keeping all their proceeds and IDs and often getting them pregnant on purpose to use as further leverage. Jeffreys alone may have fathered more than a dozen children with his prostitutes, when he wasn't busy making music videos and partying in Las Vegas, the FBI alleges.

A federal grand jury indicted four alleged ringleaders in March 2013, including Thomson, but not Jeffreys, who was indicted later for his alleged role in the ring. Unlike the other three people indicted then, Thomson was not arrested, but only because he was already in custody in New Jersey on an unrelated charge. He was released in New Jersey in April of that year and traveled back to Boston.

According to last week's indictment:

"Jeffreys believed that Thomson had cooperated with law enforcement in New Jersey and directed the shooting of Thomson, to prevent Thomson from providing information regarding him and Norris to federal law enforcement. Jaquan Casanova a/k/a 'Cass,' 'Jeffy,' or 'Jeffy Joe,' carried out the shooting at Jeffrey's direction. Jeffreys and Casanova intended to kill Thomson."

In court documents, federal officials detailed the techniques the men used to keep the girls and women under control, including:

"Jeffreys and his co-conspirators frequently used hotel rooms, often near highways, for the girls and women to engage in prostitution activity. Jeffreys often stayed in an adjacent room, in the bathroom, or on the other line of a phone left connected in the room, in order to monitor the activity in the hotel room. He made sure that the girls and women who worked for him were aware of his ability to monitor what they said and did when they were not with him. This was a technique he used as part of his scheme to control the girls and women."

An affidavit from an ICE special agent discusses the working relationship between Jeffreys and Thomson - and a third alleged ringleader:

"Jeffreys worked with other men to share resources, such as car rides, hotel rooms, and the payment means for the online advertisements. Colloquially, such relationships are often referred to as 'pimp partners' or 'p partners.' Jeffreys taught other men, including Darian Thomson, a/k/a '80,' and Corey Norris, a/k/a 'Case,' how to engage in sex trafficking. Thomson and Norris transitioned from assisting Jeffreys in his operation to harboring, transporting, obtaining, and maintaining girls and women to work directly for them. The men continued their affiliation. however, and continued to share resources. On occasion, girls and women would move from one of the men to the other."

According to an FBI affidavit, Jeffreys' criminal career dates to his early teens - his first conviction came when he was just 13. Before he turned 18, he had racked up a record that included assault and battery, armed robbery and assault and battery with a dangerous weapon.

The feds say prostitution has increased in the Boston area in recent years, in part due to crackdowns and violence related to drug and gun sales:

"[B]oth street gang members and others who regularly engage in criminal activity in the Boston area have become very wary of other means of illegal income, such as drug or gun sales. These individuals are aware that drug or gun dealing is a dangerous enterprise, drug dealers are at risk of violence from buyers, sellers and rival dealers. Furthermore, especially with the mandatory minimum penalties applicable to drug and gun possession, drug dealers fear the legal consequences of their activities. In contrast, many individuals view pimping as unlikely to result in criminal prosecution and, in the event that it does, unlikely to result in any kind of significant penalty."

Although the indictment does not provide information on how Casanova became part of the operation, it does say:

"On January 12, 2015, a federal agent from United States Immigration and Customs Enforcement/Homeland Security Investigations and Detectives of the Boston Police Department, who were jointly investigating the shooting of Thomson, interviewed Casanova and asked him about his relationship with Jeffreys. Casanova told them that he had not seen Jeffreys since they were in the same location in 2011 or 2012, that he did not know him well, and that he did not even know where he lived in 2013. This was false, misleading, deceptive, ficticious, and fraudulent as to a material matter, as Casanova had an ongoing relationship with Jeffreys in 2013, had seen him multiple times, and had spent time at the apartment that Jeffreys lived in during that time."