Almost a year after an FBI agent shot and killed, under suspicious circumstances, a crucial witness in the Boston Marathon bombing case during a botched midnight interrogation in an Orlando apartment, serious questions are being raised about the FBI agent who fired seven shots into Chechen immigrant Ibragim Todashev last May 22.

Two investigations, one by the FBI itself and one by the Florida Attorney General’s office, exonerated the FBI in the shooting death, claiming the agent, never identified, had been acting in self-defense, when Todashev allegedly ran at him with a raised broom handle.

Now, in an excellent piece of investigative journalism, the Boston Globe has uncovered the identity of the agent, 41-year-old Aaron McFarlane, who joined the Bureau in 2008 after retiring on a $52,000 lifetime annual disability pension from a short stint as an officer in the Oakland Police Department.

Aside from the question of why someone who passed through the rigorous training program the FBI runs for its recruits at Quantico, VA would also qualify for a lucrative pension, it turns out that McFarlane also has a pretty checkered past at Oakland’s Police Department — a police department that has such an extraordinary record of corruption and brutality, that since 2012 it has been operated under the supervision of a federal court “compliance director,” whose job is to see that officers don’t brutalize residents or violate their civil rights.

McFarlane, the Boston Globe reported, did more than that as an Oakland cop. The paper reports that during his four years with the Oakland Police, he was the subject of two police brutality lawsuits and four internal affairs investigations. the paper found also that McFarlane, as a defense witness in a corruption trial, pleaded the Fifth Amendment against self-incrimination in refusing to answer questions from the prosecutor in that case, which involved officers.

The trial in question was the biggest corruption scandal in Oakland’s history. Filed in 2000, the case involved four police officers who called themselves the “Riders,” who were accused of beating and kidnapping people, making false arrests, planting evidence and falsifying police reports. The case ended up being short-circuited with no convictions under a settlement that had the city of Oakland paying damages of $10.9 million to some 119 victims of Oakland Police officer’s abuse and deceit, and with the whole department going into receivership.

According to the Globe’s report, the court transcript shows that when prosecutor David Hollister tried to ask McFarlane on the witness stand about a police report he had filed which appeared to have been falsified in order to “drum up a reason to arrest a man,” McFarlane pleaded the Fifth.