The informant said associates in Compton had told him that it was a contract killing ordered by Knight. According to an LAPD summary of his statement, he said the gunman had a Middle Eastern-sounding name -- Amir, Ashmir or Abraham.
He said the assassin belonged to a security force associated with the Nation of Islam and was also a bodyguard for a drug dealer named Bay Gardner.
The gunman lived near "Greenleaf and Johnson" and hung out on "83rd Street in Compton," the informant said.
There were signs that the information might not be reliable. There is no 83rd Street in Compton. No one by the name of Bay Gardner sold drugs in the city during the 1990s, according to gang and narcotics detectives who patrolled Compton then.
LAPD investigators put the informant's statement in a file along with other leads. Six months later, Psycho Mike was released from jail.
David Mack was an undercover narcotics officer who seemed to have a bright future at the LAPD. Then, in December 1997, he was charged with robbing a Bank of America branch of $720,000. He was convicted and sentenced to 14 years in prison.
Detectives investigating the Wallace killing began to suspect that Mack might have played a role in that crime too.
He owned a black Chevrolet Impala similar to the one seen speeding from the murder scene. A witness, shown a photo of Mack, said he thought he had seen him outside the Petersen museum the night of the shooting.
The visitor registry at the Metropolitan Detention Center held another clue. On Dec. 26, 1997, 10 days after Mack's arrest, Amir Muhammad had paid him a visit. The two had been student-athletes at the University of Oregon, and Muhammad was godfather to Mack's two children.
Then-Det. Russell Poole remembered that the informant had listed "Amir" among the possible names of Wallace's assassin. Poole pulled a driver's license photo of Muhammad and compared it to a composite sketch of the killer based on witness descriptions. Poole thought they looked alike.
On Jan. 21, 1998, two detectives went to see Psycho Mike. They showed him six photographs, including Muhammad's, and asked him whether he could identify the "Amir" who was said to have killed Wallace.
The informant circled three photos, one after the other, records show. He picked Muhammad's photo last.
Witnesses shown a photo lineup are supposed to make a single choice, according to police investigators.
The detectives who conducted the photo lineup declined to comment. However, people familiar with the investigation said the informant claimed to have known "Amir" for 12 years.
The detectives later told associates that they considered the identification worthless. But Poole thought it was significant. Combining it with other tips, he developed the theory that Knight and Mack had conspired to have Wallace killed, and had enlisted Muhammad as the triggerman.
Muhammad didn't seem to fit the profile. He was a college-educated mortgage broker from Virginia with no criminal record or any known ties to Knight or the rap world.
Still, Poole persuaded his superiors to let him explore his theory. LAPD officers searched Death Row's offices and several of Knight's homes. No evidence of a connection to Mack, Muhammad or the Wallace slaying was found.
Poole's fellow detectives shifted their attention elsewhere. Poole resigned in the summer of 1999. He later sued the LAPD unsuccessfully, alleging that he was forced out as part of a cover-up of police involvement in the murder.
In December 1999, The Times published a front-page article reporting that Knight, Mack and Muhammad were among the possible suspects in the slaying. A Times article six months later quoted an LAPD detective as saying that Muhammad was no longer a suspect.
Poole, meanwhile, continued to promote his explanation for the killing. Author Randall Sullivan examined Poole's hypothesis in a 2002 book called "LAbyrinth." British filmmaker Nick Broomfield followed with a documentary, "Biggie & Tupac," in which the former detective plays a central role.
Poole has shopped a screenplay about his role in the case, titled "A Detective's Requiem." He is also serving as an expert witness for the Wallace family in its lawsuit. He declined to comment for this article.
An Alleged Confession
In the summer of 2003, a VH-1 television special featuring Poole caught the attention of Philip J. Carson, an FBI agent in Los Angeles. Carson got permission from his superiors to launch an investigation.
Through an FBI colleague, he became acquainted with Psycho Mike.
Agent Timothy S. Flaherty had been working with the informant on a gang investigation. At some point, the Wallace slaying came up, and the informant said he knew who the killer was.
In the fall of 2003, Flaherty drove Carson to the informant's home in Norwalk to meet him, according to the deposition.