"Up until this year, the oldest guy we had arrested was 36," said sheriff's Lt. Erik Ruble. "We knew our guy was older, but not [73]." [Updated at 7:34 p.m.: An earlier version of this post said Scott was 74. Scott, who was booked on suspicion of felony vandalism, will be 74 next month.]

Deputies involved in a saturation patrol this morning at the downtown 7th and Metro Center subway station encountered the septuagenarian suspect, later identified as 73-year-old John Scott of Los Angeles, as he was putting slap tags in one of the main stairwells at the transit hub.

For the last seven months, deputies assigned to the Special Problems Unit of the Sheriff's Transit Bureau have been trying to determine the identity of an "older" vandal who had been placing orange and black "Who Is John Scott?" stickers on buses in Baldwin Hills and other areas concentrated on the Westside of Los Angeles.

Calling him the oldest tagging suspect they have ever captured, Los Angeles County sheriff's deputies arrested a 73-year-old Los Angeles man for allegedly putting "slap tags" on the inside of Metropolitan Transportation Authority buses.

Ruble said Scott was caught with stickers in his pockets as well as a black brief case, which appears to be similar to a case that is pictured on the whoisjohnscott.com website.

Investigators said they were not sure how long Scott had been vandalizing buses or the particulars of his life story. But Ruble said deputies believe Scott was driven to tag by the same motivation as his younger cohorts: "fame and notoriety."

"It just goes to show, the graffiti culture in Los Angeles is not age-specific and is very diverse," Ruble said.

Seven months ago, deputies began noticing "Who Is John Scott?" stickers being placed on light poles, bus benches and even on the seats of the MTA buses themselves. Ruble said many of the stickers are hard to get to and required dismantling equipment to remove.

With a little research they found that their vandal had created a website selling the mystery of his identity as well as T-shirts, baseball caps and the slap tags.

"Who am I? John Scott -- world traveler, entrepreneur, producer, but, above all, mystery -- an ordinary man with an extraordinary idea of himself," read a description above a picture of a man dressed in black, his face hidden and a question mark over it. "A real person with a real history, he is also you and me, the face in the window, the voice on the bus."

"The mystery exists no more," Ruble said.

-- Andrew Blankstein

Photo: Tagging suspect John Scott. Credit: Los Angeles County Sheriff's Department

More breaking news in L.A. Now:

Personal data of Cal Poly Pomona applicants inadvertently put online

Metrolink board delays decision on fare hike after thousands protest

Scores of O.C. teens picked up in 'scared straight' curfew sweep

U.S. Forest Service report: Station fire terrain too steep to fight safely