The FBI has responded to Baltimore Police Chief Ken Davis’ request to investigate the execution of homicide detective Sean Suiter. In a letter reported by the Baltimore Sun, the bureau determined that there was no direct evidence linking Suiter’s murder to his scheduled testimony in a police corruption case.

“We believe it prudent for your office to continue as the lead in this investigation, with our current commitment to assist and support you fully, including providing FBI analytical, forensic, and investigative support,” FBI Assistant Director Stephen E. Richardson reportedly wrote to Davis.

The FBI vowed to “take appropriate action” should something change the decision, Richardson said.

Suiter was shot and killed on Nov. 15, one day before he would have taken the stand to testify against fellow officers. Two weeks ago, Attorney General Jeff Sessions said that the FBI would “probably” takeover the investigation.

But the FBI didn't find a connection between the 43-year-old father's murder, and the federal corruption case involving more than half a dozen Baltimore officers.

Davis was among several to request the FBI's assistance in the case, including Suiter's widow, Nicole Suiter, Baltimore Mayor Catherine Pugh, and various city and state officials.

In his letter to the FBI published on Dec. 1, Davis wrote that he was becoming “increasingly uncomfortable” with BPD homicide detectives not being privy to “all of the facts known to the FBI” and the U.S. Attorney’s Office in regards to Suiter's murder.

Authorities have yet to uncover any physical evidence that could lead them to a potential suspect.  However, Davis and Pugh might commission outside “experts” to oversee the investigation.

Though Davis has acknowledged skepticism surrounding the circumstances of the case, he hopes that the FBI’s decision will clear up theories tying Suiter's “pending testimony” to his slaying.

“If Detective Suiter’s pending testimony was somehow a factor in his death, I believe the FBI would have taken [the case] in a heartbeat, and I believe they would have taken it in grand style,” Davis said. “I think they would have brought in every resource at their disposal to Baltimore to get to the bottom of it. The fact that they didn’t tells me that they don’t believe it.”