They were released only to be followed on the highway and shot dead. Attorney General Robert Kennedy who was informed of the disappearance of the three men, arranged for Joseph Sullivan of the FBI to go to Mississippi and investigate the situation together with FBI Meridian-based agent John Proctor. Their findings would be splendidly presented in Court by John Doar, who prosecuted the federal case. Local officials were not sympathetic with the case and showed little interest in finding the ones responsible for the murders. Nevertheless, federal interest in the case was overwhelming, thus the investigation was impressive and finally led to the discovery of the killers.

The population of the country was reluctant to offering any kind of information regarding the killings; in fact, it was children who gave the investigators the most clues. The two agents used tactics such as the observation of the sheriff's behavior as he was under heavy suspicion but could not be directly linked to the murders. Although he did not crack, information soon came from inside the Klan. James Jordan, a member of the KKK came forward and was confronted with investigators during the course of five rough interviews. At the end he was aware that his only chance to avoid going to prison was to give the full story. In recent years there have been several...

This case was seen as a key to breaking the wall of segregation throughout the South. I believe that the tactics employed by the FBI were suitable for this particular case. The aim of any investigation is to reveal the truth which is always ethical hence I think that the investigators were obligated to take any measures as to uncover the truth and find the ones responsible for the three murders.
Hays, Tom. "Mob moll says Mafiosi Helped FBI." Yahoo News, October 2007. http://news.yahoo.com/s/ap/20071029/ap_on_re_us/mob_fbi_agent

Linder, Douglas. "The Mississippi Burning Trial (U.S. Vs. Price et al.)." University of Missouri: Kansas City School of Law, 2000. http://www.law.umkc.edu/faculty/projects/ftrials/price&bowers/Account.html

Mississippi Burning." Spartacus Educational. http://www.spartacus.schoolnet.co.uk/USAburning.htm

Mississippi Burning." AfricanAmericans.com. http://www.africanamericans.com/CivilRightsSlaying.htm

The Ku Klux Klan: A Hundred Years of Terror." Indiana University: Southern Poverty Law Center, 2000. http://www.iupui.edu/~aao/kkk.html