A fugitive bank robber crosses the t's and dots the i's on his demand notes so well that law enforcement officials call the suspect a "Good Grammar Bandit."

"It's well punctuated, there's proper sentence structure, the spelling is correct," FBI Denver spokesman Dave Joly told ABC News. "He did a nice job."

Denver law enforcement agencies and the FBI Rocky Mountain Safe Streets Task Force are investigating four recent bank robberies in the metro area believed to be committed by the same individual, according to a task force news release.

The agencies are working to confirm that the unidentified individual, who was believed to be unarmed, also attempted to commit a fifth bank robbery, Joly said. All the alleged crimes were committed in the stretch of a week with the latest occurring Monday morning.

(Courtesy: fbi.gov)

Investigators have not only matched the suspect with photos captured from surveillance video, Joly said, but also have discovered similarities among the demand notes.

Joly would not reveal the contents but confirmed that the notes were typed, clear and concise. "A lot of other suspects have bad grammar," he added, explaining their sometimes illegible penmanship that requires verbal translation for the bank teller.

Investigators have declined to say how much money the Good Grammar Bandit has gotten away with, only that it's minimal and is generally what's in the teller's drawer.

Such nicknames are nothing new among law enforcement officials. In 2009, the FBI nicknamed a repeat offender the Shaggy Bandit, for instance, because of his resemblance to the Scooby-Doo character. He was subsequently caught.