SPARTA, Tenn. -- The Channel 4 I-Team has learned that a Sparta police officer was fired and placed under state investigation for alleged misconduct during a homicide investigation.

Video: Ex-Officer Investigated For Fake Subpoenas

Documents obtained by the I-Team suggest the officer was abusing his power to find the source of Internet gossip involving him and the case.

Tennessee Bureau of Investigation spokeswoman Kristin Helm confirmed the target of the investigation is former Sparta police Officer Dale Dodson. Dodson was fired from the department for official misconduct earlier this week, according to Sparta Police Chief Jeff Gooth.

"We're looking to see if he either overstepped his bounds in authority as a police officer or whether he didn't,"Helm said. "It's an ongoing investigation, of course, at this time."

The homicide case involves the unsolved killing of Terry Sullivan, who was found shot to death in his Sparta home in January. Police initially told the Sullivan family that Terry Sullivan died from an accidental head injury. A few hours later, police ruled the case a homicide.

TBI officials would not specify the type of alleged misconduct. But Channel 4 News has confirmed investigators are examining bogus subpoenas issued in August by Dodson to the Sparta Expositor newspaper.

Channel 4 has reviewed all three of the subpoena documents in question. None was issued by a judge, and none contains a case number.

The subpoenas, signed by Dodson, sought the source of internet postings on the newspaper Web site's message board. Those postings made allegations about Dodson, such as "Dale Cheats" and "Hey, Dale," and made references to the Sullivan case.

The subpoenas seek Internet Protocol (IP) addresses, often used to identify the source of a posting.

Though the subpoenas were not issued by a judge, they were served by Dodson then filed with the Court Clerk, where Channel 4 obtained them as a public record.

Dodson was not one of the responding officers to the Sullivan homicide scene. But Gooth confirmed that he did involve Dodson in relation to a harassment complaint filed by the victim's wife earlier that day.

Police have yet to name a suspect in Sullivan's death.

Sullivan's sister, Daphne Jacob, told Channel 4 that the family was relieved to learn that officer Dodson is under investigation. She said they believe the probe is the first step toward bringing Sullivan's case to justice.

"It will help us in ways to have a little bit of closure," said Jacob. "Nothing will ever bring my brother back. We'll hurt for the rest of our lives. But it will help us to know that justice has been served and someone is going to pay for his death."

Jacob said TBI investigators have spoken with her regarding Dodson's actions after the Sullivan murder. She was told that the TBI could not share many details.

"It's very frustrating to know that someone in law enforcement might not have done something or handled something correctly," said Jacob.

TBI officials opened the investigation into Dodson last week and said that any conclusions would be turned over to the local district attorney.

Dodson was a 16-year veteran of the Sparta Police Department.

The publisher of the Sparta Expositor, Jim Shanks, said that his paper does not own and is not associated with the web site Topix, which is owned by another company. Subpoenas that were issued by former Sparta officer Dale Dodson were for items posted on the Expositor's own Web site, not the Topix site. Dodson, as Channel 4 reported Thursday, served the subpoenas to the Expositor in an effort to identify people who had posted comments about him on a forum. Those subpoenas were never signed by a judge and led to an investigation into Dodson for a possible abuse of his police powers. Dodson was fired.