Baltimore's top law enforcement officer on Friday asked the FBI to take over the investigation into the unsolved fatal shooting of a detective and York, Pa., resident who was killed the day before he was to testify in front of a grand jury in a police corruption case.

An FBI spokesman said the agency is aware of the request and had no further comment.

Police Commissioner Kevin Davis reiterated that federal authorities have told him no evidence exists linking Detective Sean Suiter's death on Nov. 15 to the "Broken Boundaries" investigation, which has uncovered alleged shakedowns by members of an elite gun squad. Authorities have said Suiter was not a target in the inquiry that has led to several indictments of officers and four convictions.

But Davis said federal authorities have kept his department in the dark about new developments in the case, which he now believes has impaired the investigation into Suiter's shooting. Davis said it wasn't until six days after Suiter's death that he learned the detective had been set to testify, and he didn't know about a new indictment that broadened the corruption case until it was made public on Thursday.

"I am growing increasingly uncomfortable that my homicide detectives do not know all the facts . . . that could, if revealed to us, assist in furthering his murder investigation," Davis wrote to FBI Director Christopher Wray.

Davis' request came the day after Suiter's funeral, which was attended by more than 3,000 mourners. Absent a quick arrest despite a $215,000 reward, the shooting has only grown more mysterious, forcing police to now address whether the 43-year-old Suiter was killed as part of a conspiracy or even the possibility he took his own life.

What is clear is Suiter's death and the corruption case have now become intertwined, and he wants to ensure the credibility of the investigation. Davis said he "understands the anxiety that something just does not jibe here," with details that don't appear to add up. Davis somberly noted that years-old "nefarious acts" on his police force "are haunting us now."

Suiter was shot in the head with his own gun on Nov. 15 in a vacant lot while investigating a 2016 triple killing in West Baltimore's Harlem Park neighborhood. Police have said he confronted a man he saw acting suspiciously. Police recovered three shell casings, all fired from Suiter's weapon, which was found on or next to his body.

Davis has said that Suiter's shirt showed evidence of a struggle with an assailant and that the detective made a radio transmission that is unintelligible but shows he was in distress. A gunshot can be heard at the end of the call. The only description of a possible suspect is of a black man wearing a black coat with a white stripe.

Asked at a news briefing if the wound may have been self-inflicted, Davis said, "We are not going to discount any possibility whatsoever. . . . If evidence leads us in that direction, we will go there. If evidence leads us in the direction of a conspiracy, we will go there. If evidence leads us to an unknown perpetrator we have not identified yet, we will go there."

Davis said that at this point, detectives do not believe suicide was the cause based on recovered evidence, discussions with Suiter's family and an examination of personal effects. The medical examiner ruled the death a homicide.

Davis said Suiter was to have testified at a grand jury considering new allegations against Sgt. Wayne Jenkins, who was indicted along with six other officers in March on racketeering charges involving allegations that they robbed drug dealers and planted drugs on people they illegally detained. An eighth officer was indicted later, and a Baltimore police cadet who left to work as an officer in Philadelphia also has been charged.

Davis said federal court papers show Suiter once "unwittingly recovered drugs that had been planted by another police officer."

That case dates to April 2010 when Jenkins said he saw a man holding money get into an Acura in what he suspected was a drug deal. The driver sped off, leading to a pursuit that ended in a crash that killed a bystander. Umar Burley and Brent Matthews were arrested.

Jenkins wrote in charging documents that he asked Suiter – who was in another police vehicle – to search the Acura. Suiter found 32 individually wrapped pieces of heroin. Both suspects pleaded guilty. Burley was sentenced to 15 years; Matthews to 10 years. Court documents said they feared "that in a trial involving the officers' word against theirs, they would lose."

On Thursday, federal prosecutors charged Jenkins with civil rights violations and falsification of records, alleging the drugs Suiter found had been planted by or at the direction of Jenkins. Prosecutors asked the court to vacate the guilty verdicts against Burley and Matthews. Burley had been released from prison in August after serving seven years; Mathews had completed his sentence.

The indictment says that after arresting the men, Jenkins told another officer at the scene "to call a sergeant . . . because he had the 'stuff' " in his car. Prosecutors now say that "at the time of the car chase, there were no drugs in the car driven by Burley. After the crash, heroin was planted in the car by a BPD officer."

Davis said he suspended an officer who had been in the car with Jenkins. He said the sergeant who allegedly brought the drugs that were planted in the Acura retired in 2012. Jenkins' attorney, Steven Levin, declined to comment on Friday.