Story highlights Detective Sean Suiter was shot a day before he was to testify before a grand jury

The reward for the arrest and conviction of the officer's killer is $215,000

(CNN) The FBI declined to take over the investigation of a Baltimore homicide detective's fatal shooting the day before he was scheduled to testify to a federal grand jury in a police corruption case involving seven fellow officers.

The seven Baltimore police officers -- members of the department's Gun Trace Task Force -- stand accused in a federal racketeering indictment of seizing money from people they have stopped, claiming fraudulent overtime and filing false affidavits.

Sean Suiter, 43, was shot in the head with his own gun after struggling with his killer on November 15 in west Baltimore. The 18-year department veteran had been investigating a killing when he noticed a man acting suspiciously and ran toward him.

Police Commissioner Kevin Davis said Suiter struggled with his killer, making a brief call on his police radio at the time, Davis said. He added that Suiter's clothing indicated he and the killer had struggled. It's not known whether the man acting suspiciously was the killer.

Suiter died the next day at a hospital.

Read More